sta rite system 3 cardtidge as good as de?

[coryinsocal]

i guess i should give some background and maybe you guys can help make a recomendation...

my pool is a 26' kidney, about 15,000g or so. problem is, it's really old. it looks nice, but the plumbing is not ideal. there is only one 1.25" suction line running from the skimmer and the bottom drain is full of gravel (below the cover). i'm not sure how it got there, but i know it's not functioning so the deep end doesn't get alot of attention. when i run the filter alot, it keeps up with the pool pretty well, but after a party or any thing less than an 8 hour cycle, it can turn bad and gets out of control easily if i don't really stay on it. it has a 3/4 horse pump that runs good, but looks as old at the pool and has a vintage sta-rite spin DE 25 sq ft. another problem i have is there is no sewage line near the filter, so for the last umpty years, the pool guy has been backwashing (well, who knows where). i'd like to not have to backwash, but i'm concerned getting away from DE and not being able to keep up with the pool as it's tough enough already.

i've been going back and forth between the pentair fns plus 36 sq ft and the starite mod cart in 300 sq ft....