Honestly, if thats the case, then you really don't have the time to be flashing custom ROM's. The process involves a bit of experimentation, trial and error. You have to back up and restore your settings when you flash a new version and you have to take the time to make sure things work for YOU.
Stability and operability also depends on the applications that YOU install ont eh ROM yourself. ALL of NRG's ROMS work very well, but when you start adding on other applications, that can affect the overall "feel" of the ROM for you.
That said, any of his recent 21xxx ROMs are going to be more stable and are based on Windows Phone 6.5. 23xxx ROM's are a bit more "beta" and are pulled from a ROM that is not naitively our phone so there are some compromises. They are also based on windows mobile 6.5.x.
There are some visual differences between the two with the 23xxx being more finger firendly.
If you want function and a little more stability...and want to dabble in custom ROMS...go with a build based on 21xxx.
If you don't have the time to experiment, stay with your stock ROM.
David