Congratulations! Our X20E is our second Jayco hybrid, and our 3rd Jayco product that we bought new. Our first was a '93 1208 pop-up, and the first hybrid was an '03 Kiwi 17a, the ancestor of your X17Z. We owned both of those trailers for 10 years each.
Jayco makes a solid trailer. Overall construction is very good. We have not had any issues that required warranty work. However, I am willing to fix small things myself rather than drag the trailer back to the dealer and leave it sit for 6 weeks. That said my only disappointment is in the details. A screen door latch that doesn't catch, a misaligned deadbolt lock, a piece of door jamb molding on the bathroom door not glued down prevented the door from fully closing.
These are things I missed on the delivery inspections. Nothing big, but a bit annoying.
Regarding periodic caulking, that's a given. In fact, periodic inspection, caulking, painting the frame, etc. are all highlighted in the owners manual as owner responsibilities. Keep up with these things and your X17Z will last many years.
Have fun! Oh, and don't forget to join the
Jayco Owners Forum.