AOKP is built from Source. Some bugs can be the same, but not ALL the same.
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I preffer AOKP. It seens faster to me.
If you don't need JB, you can try Salad Bar or WIUI or JIUI, those are great ROMs too.
btw, any bug list on AOKP now?
i keep track on Quarx but can't find a full bug list to compare AOKP and Quarx.
actually there are 3 main bugs i concern:
1. data connection bug - should be 90% solved by Quarx, still sometimes doesn't work. but i don't know the situation in AOKP yet.
2. wifi/bluetooth tethering - not working in Quarx, don't know about AOKP.
3. can't play live video on quickplay media based apps - this one may be not many foreign developers tried. i tried myTV apps from tvb.com, which can't play live video but work in video on demand. i'm using Quarx built and CM9 and CM10 both have this issue.