I use Cyanogenmod 7 on my MyTouch 4G, also 2.3.7 when my stock is capped at 2.3.4 reason to that is because they are different Kernels (Like software on a specific OS).
Though I just unlocked my phone, I genuinely love CM7..
Cyanogenmod offers so much, It uses a ADW launcher, which is available on the Play Store, so you can try it out before getting it... Only that using the launcher leaves out a lot of Key root features within the initial ROM.
You can use in-ROM software to overclock your processor and many other things to optimize your phone for performance and batter life..
Over-all Cyanogenmod 7 is a great ROM, I definately infer that you try it.
Rated 9/10* There have been some crashing issues on my MyTouch 4G, but not an issue for it reloads quickly.