XPVC isn't that heavy at all. I've been able to easily move my new racks around while they're full of snakes. No way I could ever do that with my melamine racks without destroying them in the process.
I like XPVC so much that I'm building 4 more racks next month. It never ends!
I'm building my third this weekend with another one due before I get more snakes in Oct/Nov. I love them and wouldn't change a thing after using them for awhile. I have a hatchling rack design I still need to build. Been slacking :p