I finished building UCS Tie Advanced X-1 (my daughter got tired after finishing up one part of the wings). The wings were very confusing to build because of the black parts and hard to see instructions so I can see why my daughter found it to be not very fun and gave up.
The cockpit is fairly dark and while I would like more details, it would have been pointless as you can't really see anyway. The hatch is also small and pretty much just for show. It uses flat surface for seat so to put in mini-fig of Vader you have swap it for 2X4 stud piece otherwise he would be rolling around in the cockpit.
Rear section of the fuselage is nicely details but not very sturdy. It was build on technic square and if you hold down on certain section the plate just collapse.
The ship does show some age and lack of STUD. The front fuselage section really could use smoothing off and is probably easy to do. I am thinking about mod it to make it more "modern" looking.
I love the printed cockpit piece, the stand is fairly stable. Absolutely loath the sticker sign (I used photocopy and kept the actual sticker for archive). I don't understand why for the set of this size they can't print certain part. Those stupid Planet Series have printed base for crying out loud.
I also don't think I will be picking up that many UCS set. The size and scale is just not very feasible for display. It does look impressive but I think I prefer the smaller scale ship.