A quick search should bring up lots of posts on this subject.
Neoprene - slightly better underwater (more insulation, more streamlined and maybe more durable)
Trilam - slightly better on surface (easier to don, more comfortable on warm days).
I have used neoprene, crushed neoprene and trilam suits, and am sticking with Trilam. Front entry trilam are easy to get on and off, they dry quickly, and you can use them in warmer water. I don't notice the slightly less insulation or streamlining in a trilam. With neoprene socks I can wash and dry my trilam suit inside and out, compared to trying to dry the inside of a neprene drysuit with fixed boots.
On top of the brands mentioned by Ontwreakdiver diver do look at German company scubaforce
Try to get a custom fit. Most drysuits are similar in build, regardless of the maker - so I would see which manufacturer has a representative near you who can help measure you up.
Good luck with your search.
Cheers
Rohan.