Rivets vs welded is similar to Ford vs Chevy. Airplanes have rivets and I've been in some awful old planes. Lunds are warrented forever, I believe, to the original owner. Crestliners are made in the same factory, and they are welded. they also have a lifetime warranty. In the midwest, Alumacraft are also very popular, and I think they are riveted also.
I have been considering a Lund Alaskan 1675, which is a little under 17' long. It has a flat floor--good for old mens knees--don't have to step up to the casting platform in the bow. I really want a Boston Whaler Montauk 15, but for some reason they are not popular in this part of the USA.