Hello, and welcome to the frenzy. I am not too familiar with many other kits, or glassing a body to the frame. I did however look at several different brands before deciding on a Shell Valley. They all have their pro's and con's, but I couldn't really think of any "con's" in going with SVC. Only you can make up your mind, but heres a few things that I like about the Shell Valley...
First off, you can buy a "turnkey minus", a complete kit, or basically piece by piece as it is needed. This is a plus for me, as I did not have ample room for a chassis and body while just working on the chassis. Even at 6'1" or 6'2", I still wanted the original 90" wheelbase, as you can tell a difference. Also, it seems to be a pretty straight-forward build. There are times however that you will need to call the manufacturer about something- a question about a part, an opinion or suggestion on the construction of the car, etc.. Dana, Bob, and everyone else I have spoke with has always been MORE than willing to take time out of their busy schedule to field my phone calls and help me out.
Good luck in your decision and build, but you cant go wrong with Shell Valley. Also, for a few more pointers or ideas, I have posted a link to a page on my website which might help you out as well.
Greg
http://www.gregsgarage.20megsfree.com/custom4.html