This was a fun build with a lot of unique techniques, taking me about eight hours to complete at a steady, unhurried pace. There was some unavoidable repetition (to have them match, you have to build the legs and side panels the same way), but it was otherwise a varied and engaging build. My only deviation from the manual was waiting to attach both legs to the head support platform (which you build first) at the same time, rather than after completing each one.
Overall, I'm happy with the final look, which is nicely detailed, even on the inside, and it will look good on display beside by AT-AT. It is also nice that the head can be rotated side-to-side, and the cannon angles can be adjusted, which helps you vary how you display it. That being said, only one Imperial minifig is included, but the AT-ST is controlled by two pilots in the movies (along with a commander), so that was a little disappointing.
But, to me, Lego missed a key opportunity to improve playability: Ewoks! Given the key scene in Return of the Jedi when Chewie commandeers an AT-ST with two Ewoks (which is highlighted in the manual), the playability of this set would have been much improved if a couple of Ewok minifigs (possibly with a RotJ Chewbacca minifig) had been provided alongside the single Imperial minifig.
Therefore, I consider it a bit pricy for what it is included. Had more than one minifig been included, particularly a couple of Ewoks to improve playability, I would have considered the price more appropriate.
Nonetheless, it is a worthy addition to my Star Wars UCS collection.