I have little direct experience with the Hubba Hubba, but fairly long experience with the one-person version, the Hubba. I like that tent a lot - an awful lot. It's fairly light weight (and their "UL" clones, the Carbon Reflex 1 and 2, are even lighter, if weight is an issue and money is no object.)

The side opening is the most convenient I've found in any tent. Also, the symmetrical shape of the tent and the fact that the vestibule is split exactly in half (and can be left fully open, or half open on either side you choose) makes it easy to ventilate, even in the rain. It also means that, if you're like me and don't always get the foot end on the low end of the tent, you can simply flip you pad and bag. With other tents, like the Big Agnes Copper Spur or Fly Creek, your only option is to unstake the tent, reverse the pitch, and re-stake it.

The symmetrical shape also means that you can pitch it with the door facing whatever direction you want (to take advantage of a view, or avoid having to exit into the sticker bushes, for example.) In a tent with a distinct head and foot end, in order to get the head on the higher end of the slope, you might end up with an awkward exit. (When I talk about "slope," I don't mean severe slope - just that minor difference that always seems to be there, even on the most level-appearing sites.)

I did use a Hubba Hubba a couple of times, car camping with my wife, and found it to be a very comfortable tent. Two doors is nice, so you don't have to climb over your roommate to get out. It also means you can have the fly on (for privacy, in a public campground) but leave both vestibules at least half open to get some nice cross-ventilation going. I recently bought a CR2 (which has only one door, to save weight - not a problem, since I don't plan to share it with anyone) with the intention of using it as a winter tent, when the extra room is nice to hold all the extra clothing I bring, or to have someone in to play cards on those longer evenings. I'm anxious to see how it does.

I'd highly recommend the Hubba/CR1 and, by extension, the Hubba Hubba/CR2.