I don't run a X21 but I do run a H20B and run her hard and have had no issues at all. It does run well in rough water (not Bass Cat or Champion good) very stable and fishes well. Also rigging all your stuff is super easy they run a big tube down the middle of the boat to run all your wiring.
Also Xpress is super helpful with any questions. I ran Bass Cats and Champions for years and have been super happy with my Xpress. The only thing i am not overlay happy with is the trailer.
I also run the H20B. Fantastic boat in rough and smooth water, salt and fresh. No problems at all. It's a bass hull with a center console top. There are thousands of these type boats out there but you generally only hear of those with problems, people seeking help or venting frustration. The happy ones are out enjoying the waters