Trilam or Bilam
Advantages: lightweight, dries quickly
Disadvantages: more prone to punctures than neoprene
Crushed neoprene
Advantages: very durable, drysuit material offers some intrinsic insulation
Disadvantages: heavy, dries slowly
Recreational divers who dive around lots of sharp objects/rocks and value the robustness of the crushed neoprene tend to migrate towards crushed neoprene.
Lots of recreational divers go with the trilam since the material is so lightweight which makes it easy to pack.
You really should demo several suits before buying anything. If you can swing it, you should try to test-dive a DUI trilam (TLS), a DUI crushed neoprene drysuit, one or more Bare drysuits, and the Whites Fusion. Check the manufacturer websites or talk to a local dive shop that carries drysuits to find out when "drysuit demo days" are scheduled. FYI, every suit has its pluses and minuses. If you go with the Whites Fusion suit get the replaceable neck/wrist seal system. If you go with a DUI suit, get the Zipseals. Also, consider key options such as pockets, rockboot vs. attached boot vs. DUI turbo soles, and a p-valve. Whatever you get, make sure that it fits properly. If the suit doesn't fit properly, it can be annoying to operate...and possibly unsafe. Good luck.