Pros: -Light Powered, charges VERY easily with even low light.
-No batteries!!!
-Excellent range, great for sitting on the couch, using the TV as your monitor.
-Slim profile keys with a comfortable travel.

Cons: -Not Backlit (For the price, backlighting would've been a nice option.)

Pros: I like this keyboard. It is light and keys are soft and responsive. Easy to clean with an air duster. I own this from last 4 years.

Cons: - It has a hidden 3v LIon battery that is good for 3 years (in my case 3.5 years). It is not easy to replace this battery unless you are okay to tussle with a small battery tray under the keyboard (just under the solar panels). Logitech provides 2-3 years of warranty on this product but if your battery goes beyond 3 years then you are out of luck as the keyboard is expensive, I had to use a knife to pry open the battery compartment, You need ML2032 3v Lion battery. It is NOT the same as a CR2032, which is not rechargeable.

Other Thoughts: Would recommend to other people.

Pros: This product gets and deserves 2 eggs (see numerous issues in Cons and Other thoughts). It's better to list why it gets 2 eggs than why it got knocked down 3. One of the better "scissor-type" keys I've used (laptop keyboards and these are "scissor-type" keys). Great tactile feedback, much more than any other KB like this (and I've had about a dozen "scissor types" trying to find just the right one). Is a little louder than others, but I like that. Has some weight to it, mixed with the rubber feet kept is very steady on my glass and wood desks without moving (unlike others!). It also is very compact, which was a plus for me. In addition to compact, it was very very thin! This I liked the most as it seemed like I was typing right on the desk.

Cons: See Other Thoughts: 4 RMAs over 2.5 years. Also, it doesn't seem to charge too well in a mid-level brightness room. Every 1 month or so, I have to place it on the window during 1 day (can be cloudy, still charges) to full charge - usage is about 3 to 4 hours a day. During those days I leave the house for working at client site or something. Because such an annoyance happening so often, I set my calendar to remind me once a month to "Put KB in Window to Charge"

Other Thoughts: After my purchase in 2012, I've had a long long history with these keyboards (plural). That is plural because I've gone through 4 RMAs for this board. The first one the left SHIFT key broke off (I game a lot, "SHIFT" being used for sprinting). They sent me an entire replacement - that lasted 6 days before the battery died (it wouldn't charge!!). They sent me another replacement (this time, they wanted that 2nd one back in exchange - return label, no cost so far). That's cool. Now on the 3rd version, I used it for about 6 months and it just stopped charging. About to give up, I just called again and they sent me another one. Now, this version is black (all others had a WHITE base). Cool. Except, the LEFT key broke off on day 1! Called and got a 5th. I switched to a mechanical after all these years and RMAs. I use it as a backup and setup machine KB now. If it dies again, outta warranty, it goes into the trash. FINAL THOUGHTS: Overall, I really really liked this keyboard and would be using still today if it wasn't for all the RMAs and issues. Even the charging, while annoying, was livable. But, I would not recommend this to a friend because of all the troubles. If Logitech can get their Quality Control fixed company wide (I've owned a dozen+ Logitech devices: every-single-one-had-to-be-RMA'd-at-least-once!!!!), I may recommend Logitech. But as it stands, I just used their webcam and got rid of everything else (a long long list of things).

Pros: Bought this in late 2011. Its now mid 2015 and still going strong. no issues what so ever. I didn't even realize I've been using it this long until I decided to go thru my Newegg history.

Cons: None.

Other Thoughts: Got this before the price hike. paid $30 for it in 2011 and its now up to more than $60. Even @ $60 I would buy again if needed.

Pros: - Very slim and light compared to most other keyboards (i.e., very, very portable for a non-rollup keyboard)
- Very long times between battery replacements
- Keys aren't too heavy, but aren't really light, either
- Charges rather quickly, even in low-light conditions
- A quick press of the charge button indicates whether the environment is providing a sustainable charge (green for charging, red for discharging)
- Discharge light blinks red when the battery gets low, so that you don't all of a sudden lose functionality without a warning
- Feels sturdy, and is actually a tad bit heavy, despite its thin profile. I would still avoid dropping it, though.
- Never once had a signal dropout, even when the battery was nearly dead (<5% charge) and buried underneath the mess of cables and interference known as the back of my computer.

Cons: - The black finish on this keyboard means that any sort of dust or hair that happens to land on it is going to show up
- Scratches that occur are fairly noticeable

Other Thoughts: Unlike what has been said before, the battery IS replaceable. Though the battery is indeed hard to find (and it needs to be the exact same type, to boot), the battery tray can be opened with commonly available tools, such as a flathead screwdriver. You do NOT need to take the whole thing apart to change the battery. The battery is in a tiny tray underneath the surface, in between the Logitech logo and the left solar panel.

If you are having issues with the battery, it is probably because the power switch has been turned to "off". The keyboard doesn't charge when the power is off, but the power draw while not in use is ridiculously low, so low that it won't go dead for months from its first charge cycle (as advertised). The keyboard also has a timeout function that puts it in a sort of "sleep" mode that kicks in after a little standby time, which was presumably implemented to save the battery from heavy overcharge.

I was in fact able to consistently use this keyboard in a dark room for at least a month's worth of regular use. I'm not sure if it was actually three months, but it did indeed last for a decent amount of time with little light to charge with.

As a side note, I still have one of the second-generation models from just over three years ago (among the first batch of keyboards with blue function keys and gray bezel). I've seen this thing at 0%, 100%, and everything in between. What I've learned is that you just need to keep the power button switched to "ON", and make sure to use it under light every now and then to keep a decent charge. Only turn the power off if the keyboard is going to be in a dark place where keys are likely to be undesirably pressed, such as in an electronics box, or a tightly-stuffed backpack.

Pros: I've had this keyboard for almost 4 years and it still works great! The tactile feedback is nice, the chicklet layout works well, the solar panels still give plenty of charge.

Cons: The dust/dirt does seem to really like this keyboard. Being all black everything shows up. Not enough to knock an egg off though. Still keeps its charge at 100% even through the dust.

Other Thoughts: I would highly recommend it. I'm keeping it around until it croaks.

Pros: Solar powered: It never runs out of battery! I've never seen the batter drop below 99%... hasn't even gotten close to draining even in a dimly lit room. I work at night mostly and usually with almost no light other than my computer monitor.
Logitech Quality: aka I've never had a problem it works flawlessly consistently.

Cons: it's not ergonomic (just your standard keyboard shape we're all used to), and is susceptible to spillage (although I have not tested it)

Other Thoughts: This is the keyboard to rule all keyboards!

Pros: solar

Cons: function key for shutdown

Other Thoughts: WHO THE HECK PUTS A FN KEY FOR PC SHUTDOWN RIGHT NEXT TO THE VOLUME FNKEY!!!! i bought this a while ago, maybe a year. I had to glue the F12 key in place so that i would not accidently power off the computer. Logitech you suck on this one.

Pros: Low Profile
Doesn't Need Batteries

Cons: Not particularly rugged
Needs quite a bit of light
Wimpy Battery

Pros: no batteries needed, ever. works well in low light (i mainly use at night with standard incandescent lights). good connection to the computer, no dropouts. off switch to keep it from draining when it's dark. it's slim, sleek and works without issue

Cons: the layout of the keys are a bit strange. it's not standard, so typing muscle memory keeps making me hit the "/" key or control when i'm trying to hit shift or enter. it's kinda annoying but i'll get used to it.

Other Thoughts: some people have mentioned the fact that it uses a battery that can't be replaced. i guess i'll cross that bridge when i come to it. overall, though, for the price, if this keyboard lasts me 2+ years i'll gladly buy a new one if/when this one wears out. best. keyboard. ever.