well for me it really is more of a comp specs thing than a program.... for true GI and caustics i have Carrara 2.1 and C4D....but em progs dunt help me none cause a render with GI/caustics takes a very long time 2 render....so em programs are just as useful as P5 rendering GI..i never found out how long it would take since i cancel the renders 1/4 through...um talkin about hours and hours! maybe even a day! so it really is a computer hardware problem for me....once i upgrade then maybe a 1 hour render would really seem to me like a blink of an eye since i got too used to waiting hours and hours.