Now that our guest room is gone (2nd kid on the way!), my wife and I are considering getting an inflatable mattress for when guests come over (we'd probably sleep on it, and give guests our bed). I'd like one with the pump attached for quick inflation/deflation. I see a few different models, from some in the $30 range to about $150 for the Aerobed (queen size). Naturally, of course, I'm curious as to why the price difference, as they look somewhat similar on the box. Anyone have any opinions?