A powerful phone with lots of promise...
I bought my Motorola Atrix 4G (MB860) awhile back, mainly because I liked the idea of Webtop with the Lapdock and Work & Play Dock that allows you to connect to a TV and use a wireless keyboard and mouse like a PC. However though nice at first this turned out to be a bit buggy and quite slow, especially with a few other apps running. It often took ages to switch from phone to Webtop mode, so it wasn't very convenient. Sometimes I even had to reboot first to get it to work.
At the time I bought the phone, an ICS update was on Motorola's schedule so I thought I would be able to upgrade at some point. Sadly Motorola reneged on it's promise, and cancelled particular upgrade path, eventually saying that the Atrix would not give a decent ICS experience. It seems Motorola would rather people buy a new phone than support a phone that was less than 2 years old. Naturally myself and many others were and still are outraged at this, and the hashtag #motofail trended on Twitter at the time. They did offer some trade in scheme but I'm not sure I'm even eligible for that since I bought mine secondhand from eBay.
I've found the stock Gingerbread can be quite annoying at times, especially with a few apps running in the background. I'm generally flicking between Facebook, Twitter client, and Google+ apps most of the time and maybe Poweramp if I'm listening to music. With stock firmware, no matter which player I use always had stuttering playback. I also often had high CPU and keyboard input lag. Even a quick Google search took longer than I wanted.
There are now quite a few alternate ROMs for the Atrix 4G, including variants of Gingerbread, Ice Cream Sandwich and Jelly Bean. The most well known being CM10, a version of JB, by Cyanogen Mod. I recently upgraded by Atrix to an unofficial CM10 build called Avatar, which puts a MIUI look on a CM10 (JB 4.1.2) base. I mainly chose it because it's a very recent build. Anyway I already had my phone rooted and the bootloader unlocked for a long time so I gave it a go after a particularly frustrating time with the stock Gingerbread. It didn't take long to flash and I was pleasently surprised by the results. It's absolutely blazing fast! Even with the same apps running I had on stock, it's just so smooth and a pleasure to use. I get none of the sluggish feel of the Stock firmware nor the audio lag and jitter. Poweramp works very well in Jelly Bean and also the keyboard lag has gone too. This phone certainly deserved an upgrade to ICS and even JB!
Now the only downside of the third party ROMs for the Atrix is a lack of
camera drivers, so the default camera app does not work. Other camera apps work, but have no hardware acceleration. I have installed Camera Illusion and Video Camera Illusion
and they are both stuck at 640x480 resolution. Now if Motorola could
just quietly release some drivers to the XDA devs that would be great!
Apart from the camera, and also Webtop and fingerprint reader (both of which I I'm not too bothered about), everything else works fine. HDMI video output works, it now mirrors the phone screen (no Webtop), but sound does not seem to output through HDMI anymore unfortunately.
So either I downgrade to Stock to get a working HD camera, but annoyingly sluggish OS or stay on Jelly Bean and enjoy a fast, smooth OS but no HD camera (and maybe hope it gets fixed one day) or alternately buy another phone. Slight problem I have with downgrading is I cannot find the original UK T-mobile firmware for my phone! If anyone can find a working download link, please post in the comments.
I have switched to CM10 as it is more stable than Avatar which has had a few little crashes here and there.