Most membrane suits will be trilaminate, though you do find some bilaminate suits and also ones that are straight vulcanised rubber. The Viking suits are good examples of vulcanised rubber.
Trilaminate suits tend to be a butyl rubber, sandwiched between two layers of other material. Butyl rubber is "air tight"", but isn't particular robust (and has some interesting stretch characteristics) so putting it between two other layers protects the integrity of the rubber.
So yeah, you'll see huge variation in "trilaminate" - some will use nylon, some will use polyester and so forth. Each material will come with a different weave. Even the butyl rubber layer will vary in density. All of these things will change the way the suit feels and lasts.
Hammond Drysuits have the details of the materials they use on their website;http://www.hammond-drysuits.co.uk/infop ... 10&extra=1
So for example, one of the materials they use is 160g/sqm Cordura weave outer, 160g/sqm butyl liner, 70g/sqm polyester inner. Cordura is just nylon, but the weave of the fabric is more resistant to abrasion etc.