Why speedy and modded roms are made only on CM7?
Is there some limitation or restriction?
CM7 roms are the Android Gingerbread based roms. Due to our Ace's hardware restriction, it can only run Gingerbread roms to its maximum potential. That is the exact reason why Samsung didn't provide an OS upgrade after the Gingerbread 2.3.6. This means no other roms, be it CM9, CM10 or CM11, will be able to run as fast and stable as Gingerbread roms(CM7+ Stock). You will be able to run CM9, CM10 or CM11 on Ace because they are twerked to such an extend inorder to reduce lag. Not only would all features not work with them, but also it won't be as fast and stable as Gingerbread roms. But there are users who loves the looks of CM9 and above more than CM7. So in the end its upto you to choose. Hope I Helped