I don't own any of them but I've had a good look at them instore at my local.
The cover is a nice matte semi-gloss finish and the bound feels nice and strong. I really like this size as opposed to the smaller omnibus editions but that said I couldn't justify the additional spend given I own the original trades of most of these as well.
But I would highly recommend them. Oddly enough the Aliens edition doesn't have the additional full page artwork by Dennis B that was in the Omnibus version.