That's what I like about building. Not many RTR RC's come with electronics I would actually buy separately, so buying a RTR just means spending money on stuff I don't want.
I like the realism of crawlers. And upgrading them can be fun, using parts on it that were made for something else. My WPL...
I prefer kits myself. I don't have any resl 1/10 crawlers, but would love to grab a TRX4 kit or an SCX10 III. I don't have anyplace here to run them, but it would be fun to build one.