Considering what we've been given up until this point (halfway through the season), I enjoyed it. They went somewhere, did some exploring, encountered a bizarre mystery, lost someone (a "red shirt", so-to-speak) and left us with an ominous tease to a potential follow-up episode. I'll give it 4/5 stars.
My only gripe with this episode is the guy going around with the floating camera. It distracts/detracts from the feel of show...