I personally love it. It gets a lot of hate for the motion sickness thing, but, like you said, that's part of it's "boldness." I get what you're saying about the "clinical" feel but I don't mind it too much in a science-y environment.Mission: Space is a bold attraction in the vein of Tower Of Terror and Expedition Everest. It's way better than Horizons ever was but I just can't put my finger on it; it lacks heart. It lacks emotional appeal. I don't know how everyone else feels but I simply can't connect to Mission: Space the way that I do to some of WDW's best attractions.
I enjoy Gary Sinise's work but his narration is just too clinical.