Pros: Small footprint, excellent capabilities. I was using Raspberry PI for simple tasks and always found them a bit lacking as far as CPU power. For a little more money you get an extremely capable appliance with an HDMI port and room to expand the DRAM. I purchased a 1.25V 4GB 204 pin SODIMM, reflashed the BIOS to opensource SeaBios, and installed Linux (Elementary). This machine performs desktop operations flawlessly. I am not going to game on it, but for connecting it to my TVs HDMI port, it is perfect.

Cons: Only 16GB SSD, fine for media center, but for desktop, you should connect a nano flash to one of the USB 3.0 ports.

Pros: - good value for money on sale
- upgradeable (m.2 SSD and Memory)
- easy to take apart, though many many screws
- 2 SODIMM slots for DD3L - potentially up to 16G of RAM
- CoreBoot so they boot very quickly
- somes with mounting bracket
- Good for streaming content (h.264)
- upgrades handled by google
- comes with 5GHz 802.11n (way better than chromecast over crowded 2.4)

Cons: - slightly noisy compared to ASUS
- chromeOS (though to some might be an advantage)
- annoying to take apart but no glue or weird clips
- keyboard and mouse are poor and wired
- power LED is horrendously bright

Other Thoughts: I got mine on sale. I have other chromeboxes which I've repurposed as small quiet and useful general purpose linux boxes. This one is staying a chrome box. I specifically bought this to stream video to a 1080p TV. It does this job admirably with Chome OS 42.
If you like ChromeOS, then you already know what to expect. Low maintenance, regular updates and the ability to nuke it from orbit quickly and easily using a built in factory reset mode. Streaming content via a browser is a snap.

Pros: Small device, includes cheap but functional keyboard and mouse for about the same price as other Chromeboxes, lean OS, simple connectivity.

Cons: Surprisingly noisy. It seems there isn't really a fan profile that throttles the small, high RPM fan under light load. No matter the CPU load, it's always the same speed/noise level.
This unit just would not render 1080p resolution correctly. Connected to either an LCD monitor or my plasma TV (both native 1080p), text and graphics were blurry, with no options in ChromeOS to modify DPI scaling. The keyboard/login commands to get into "advanced" mode for the other Chromebox brands don't work on this Acer. For Kodi/OpenElec hackers, this unit would also be tougher to modify/upgrade (didn't try it on this unit since I wasn't happy with the noise level anyway). Since this was to be a HTPC/Streamer connected to my TV, the above 2 issues are deal breakers for me. I'll be getting an Asus as a replacement.

Pros: Sleek and stylish. Small dimensions work well, even able to mount directly to back of some monitors. Low power usage *(check cons)

Cons: The reason I had to return the item was due to trying to use HDMI to DVI-D or DVI-I converter cable. The system uses very little power. The Video output signal throws too little voltage through any kind of converter cable.

Wish ACER had been upfront with compatibility monitor issues.

Other Thoughts: Tried multiple monitors and two different converter cables. If you do not own a monitor with native HDMI or Display Port video in, you'll have to skip this. Even though the monitor was also an Acer x223-wb, not enough power was sent through converter cable to show on monitor(s). The Chromebox worked fine on a standard HDMI tv. The converter cable worked fine from desktop GPU to same monitor. The only conclusion that I and a local PC tech could come up with is the system simply doesn't throw enough volts through video-out ports to use converter cables. ACER tech team really didn't have any answers other than buy a new monitor........... That's why product doesn't get 5 eggs.

Newegg was very generous with RMA sequence. Will keep me using The Egg from here on out.