Pros: Simple and easy to use.

Cons: Doesn't perform basic function of allowing multiple monitor hookups. Sure, some people with some configuration - it works fine for - but 36+ pages of the same support issue at Lenovo back me up:

https://forums.lenovo.com/t5/ThinkPad-T400-T500-and-newer-T/T540p-T440p-UltraDock-external-display-issues/td-p/1368847/page/36

Pros: - It has a lot of ports.

-I like the general design of lenovo docks where you can just place the laptop down on the dock without having to hook anything up.

Cons: As the title says, Lenovo makes two major steps backward on what was a good design.

- As others have stated if you place the dock on a flat surface your laptop can disengage from the dock. I glued rubber stoppers to the bottom which both provided elevation and friction to help keep the dock from sliding around when putting the laptop on the dock and taking it off.

- This dock mostly blocks one of the two main heat exhausts on the laptop, causing it to overheat. I have had my computer shut down due to this over heating and I have lost work because of it. Not to mention given the extra damage being done to the CPU, I don't know how much this will reduce the lifespan of my CPU or laptop.

Pros: Works as expected, nice selection of Video out's

Cons: None at this time

Pros: Multiple video connection options built in, VGA, DVI, 2xDP, and HDMI. I like to option of 2xDP because it seems a bit more future proof than 2xDVI.
Easy to setup 2 monitor plus panel. I am using 1xDVI, 1xDP to DVI adapter and the built in panel on a W540 K1100. Works great for 3x1080p. No issues on wake with anything connected to the dock.

Cons: Audio port placement. I knew this going in, but the audio port on the side of the dock like prior models would have been easier to get to if you don't always have headphones plugged in. Currently I have mine plugged into the headphone jack on the actual laptop.
The laptop is a little loose on the dock, you can lift the end front of the laptop and get a little wiggle. I would recommend keeping the dock and the laptop on a wide flat surface because of this. I had originally planned on putting the dock and laptop on a riser but scrapped that as the riser was not long enough to support all the way to the front of the laptop.

Other Thoughts: Having used several Lenovo docks previously with R61s and T420S models I knew what I was getting into. Occasionally the do have some video issues, but none so far with this one.

There is a firmware update available for the DP hub in the dock which may be needed if you are having issues. I have not experienced any so I haven't bothered to check the revision installed on mine.

Pros: I can seat my W540 the first try every time and disconnect with one push. It's a lot easier to use than the Dell and HP docks I've had in the past. More than enough USB and video ports in the back. I like the design of the thing. It has a low profile.

Cons: Headphone jack is in the back but it would be more convenient for on the side. If you have speakers it would look nicer in the back though. Maybe they should have both?

Other Thoughts: Laughing at other people who complain about large gaps and disengages. What are you doing on your desk that's causing you to knock your laptop around? Treat your equipment better.

Pros: Perfect fir for my Lenovo W540 laptop. Flawless operation.

Cons: None to speak of. No glitches or incompatibilities found yet

Pros: It's nice to plug in the laptop and have it plug in all the peripherals, power, network, etc.

Cons: This dock has the same types of connectors as the 4338-35U, but those can't be used anymore since Lenovo got greedy. The plug between the dock and laptop itself changed. Now I'll have a bunch of useless docks that still work perfectly as my laptops start needing replacement.

As another reviewer mentioned, there is a large gap between the laptop and the dock itself. Makes it seem like it's not connected well. Might take a few tries to get it seated right compared to the previous models where you could just set it down and it would lock into place.

Other Thoughts: Defective upon arrival. While all the connectors worked, it would not charge the laptop as it was supposed. I have ordered a replacement.

Pros: Ports

Cons: The W540 constantly disengages - needless to say that is a serious problem. There is almost a .25 inch space between the W540 and the base. Any movement causes the connection to be broken. I finally put a few silicon feet on the dock to force it flush to the W540 and it has helped.