I picked up Spaceteam a couple of days ago, and it's a lot of fun. It's intentionally goofy, though.
I've been wondering about Artemis. How complicated or sim-like is it? I expect to play it with my daughter most often, and I could see her playing it with a roomful of cousins at Christmas, but they're mostly in the 6 - 10 range. I know they'll enjoy Spaceteam, but I'm not as sure about Artemis.
Also, for a similar feel in a boardgame, Space Cadets
was just released. It seems this one would be best with 5-6, so I don't know that I'll be picking it up. It's supposed to be a lot of fun, though.