[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] Gatondroid:
Well...well... I've been using CM11 for my SGS3 i747m for a month, and this is what I've found so far.

Yours, guys, might work different, but as so you might encounter it pleasant, I think I do not prefer it over the currently 4.3 OTA.

Pros:

Ultra Fast: As it was heard about, the performance of the cell phone was indeed improved. Switching over the apps is quite faster than with the previous 4.3 OTA or 4.1.2 OTA.

Neat and Elegant: the presentation of the main screen, the menu, the lock screen, and the camera looks and feels smooth and pretty.

(Personal) Scrolling wallpaper: Yes I know you can install other launchers and be able to have a side scrolling wallpaper on the main screen, but I actually prefer it to have it without any extra installment.

Accessibility: As with the previous 4.2 and 4.3, pulling down the status bar provides you with useful shortcuts to enable or disable, for example, Wifi, Mobile data, Lamp (torch), rotation, Airplane mode, and also, if you go to Settings, then to Interface, then Quick Settings panel,, in the section Static Tiles: Tiles and layout, you can customize and add more shortcuts to this previous mentioned.

Google Now: Practically like Siri for Iphone, just pretty much more for searching over the web, but also lets you activate alarms, or call, or message contacts, the normal thing.

There are more cool features, but this I feel are in my opinion the most important ones... now...

Cons:

I'm very picky at this, and i cannot resarch on how to fix this problems very much because 1: I'm new to the XDA developers... 2:CM11 for SGS3 is still quite new, and not much has been said about it.

1: You cannot add new homescreen pages, unless you take a widget or app, and slide it towards the right end of the homescreen, something it really bothers me a lot, because I just want to be able to look at my background.

2: Homescree also: if you slide across of either end of it, it won't take you to the beginning, or end: i.e. homescreen does not loop across, so if you go right you can only go right and stop.

3: Lockscreen shortcuts: the unlocking feature is neat, but as it seems it would allow you to add more around the crcle, you can't, and are only limited to only 5 of them. You can change them of course.

4: Cannot change Lockscreen wallpaper: Yeap, now the homescreen and lockscreen share the same background. There is no remedy.

5: There is not task Manager: this is a huge one, because I loved how everything was so slow, and you would only long-press the home button, tap on task manager, and free the RAM. NOT ANYMORE. Anyway, something similar has been added. Same process, long-press home button, and when you see the apps you have working, in the up-right corner you can see some tiles. Tap on them, and all apps close. I must imagine it also frees the RAM.

6:THE MOST IMPORTANT ONE FOR ME!

THERE IS NOT DLNA/UPnP BUILT IN FEATURE!!!! :( THE GALLERY, THAT PLAYS EVERY VIDEO/PICTURE ON THE PHONE LACKS OF THIS GLORYFIC(yes, I made up that word) FEATURE. This button, which appeared as a rectangle with an "a)))" like so, let you share any pic, or video you had in front of you directly to your WIFI DLNA enabled TV/Xbox360/PS3... it sucks, AND ALSO, this feature, for me more like a treasure, was also built-in in the Music Player of 4.1, 4.1.2, 4.2, 4.3 android. It's gone, as there is not such app on this. Yes, I know there is a possibility of flashing the Player, I tried from many sources, specifically for i747/i747m but non luck.

If any interested from my last critic, "Streambels" is a very neat app that actually allows you to do so, not such in a fancy and easier way, but it does the job. There is also flippsHD, and iMediashare Personal, but so far I'm loving Streambels.

Well, that's it.

P.S.: I reccomend to NOT ENABLE THE CAST SCREEN HIDDEN FEATURE (Settings, Display & lights, Cast screen). I heard this were to let me to mirror my screen on the TV, and pretty much do the same as with my last critic. What it does?? Ahh, it just disables your Wifi internal modem, forbidding it from connetct to Wifi, and even from forget the already connections. For me I just happen to realize that that nightmare, Cast screen was causing the big scary problem. Don't do it. Or just try and tell me if it works for you.

I'm done, thanks for reading.