We debate staying at the Disney properties or the hotels on the monorail, but ended up with Henn Na in part because of price, but also the novelty of the place.
The novelty wears off - it's a small hotel with small rooms (typical for Japan), and the dinosaur theme is only present in the lobby. But it is fun seeing the dinosaur robots every time we walk through the lobby.
The check-in robots can automate your check-in, but only if you're prepared, as they can't really go off-script. It asks you to type in your name, and it has to be the exact full name you booked with or it will summon a staff member to complete the process with you, which kind of breaks the fun.
It's too far from Disney to walk, in my opinion, and the shuttle is infrequent. But the #9 bus stops right outside and will get you to the monorail station in about 5 minutes, so that's what we did most of the time.
There are restaurants and convenience stores very close to the hotel.
They make a big deal about their in-room robot, but we couldn't get it to do anything reliably.
Novelties aside, it was a clean, friendly, efficient hotel and we have no complaints. Would recommend.