The SEM is excellent stuff, I havent used it but Mark and 2Bad used it and it looks excellent. I have used the Raptor twice and recommended it to several others that have been very happy with it. It is also very affordable and a 2 part is almost always going to be of better quality than a single. I used the tintable and it was very easy, did a grey for the floors and white for the inside of the hard top. You can also get extra quarts if needed. Here are pics of the grey liner, so far so good. The texture is very nice, a little slick but not sandpapery like linex. I'd recommend a rubber mat to go on top if you dont want your stuff sliding all over the place.
The fourth pic shows the texture, its actually a pic of a plop of poop that got dropped when I rolled it into the sun for a few to get the fumes dissipated.
As far as for prep, the Raptor is real easy and can even be touched up later by just spraying over top after a good cleaning. I sprayed mine just after painting, figured the overspray would make for a very good surface and it did.