I try 15 roms and I am on this rom from almost a year and I don't even think to flash a new one. HD2 have his limits and always update to the newest rom is not a best choice. BTW is not the EVO ICS.
About battery, look here:
http://xdaforums.com/showthread.php?t=2611064
It not bother me how many application or games I run in the same time because I don't need that, what I need is run everything on 1 rom and mine do that. I got 5 desktop windows with Next Launcher + 6 widgets + 3D flip Clock which looks like sense.
Ram depend of the setting you use and how many widgets you use and which launcher, so it can't be calculate like this just saying 260-290, if I don't use anything I got even less but now I got 100mb left and some up and down. Anyway Android will manage the ram when needed.