Pros:
Friendly English-speaking staff
Bed was clean and extremely comfortable; probably the best I've slept on in Japan
Room was pretty big and had a large window that overlooked the bullet train tracks
Air-conditioning worked well
Cons:
(Non-smoking) room had a bit of a musty/smoky smell, although it went away after opening the window and running the AC for a bit
Distance to hotel is walkable from Takasaki Station, but it's not an easy one (probably easier to take a taxi from the West Exit)