I got one of these things for Christmas from my wife's family secret santa:
The way this thing works is pretty interesting. At the bottom are some coals. You put wood on those coals, and they smoke. At the top is your food. In between is a bowl of water. The water acts as a moderator for temperature and as a humidifier.
So I've now smoked meat on this thing twice, in the dead of winter. The first time, I did a whole chicken, and it came out looking like this:
I was a little intimidated at first, but I watched a bunch of videos and everything turned out great! I broke all the rules, looked at the food too many times (every half-hour the first time, every hour the second time), fussed with the coals too many times (well, once, the first day), bought and used the wrong charcoal (lump, should have just got the regular stuff) and the wrong wood (chips, should have got chunks), and it was still moist and delicious. Frankly, smoking is a lot easier than grilling!
If you have space, you should get one of these things. They're easy to use. They take forever, but you really don't have to screw around with them that much once you set them up.
Here's my rub recipe: equal parts salt, sugar, cumin, garlic, oregano and New Mexican red chile powder. I admit I did use a dash or two of MSG (it's fine, really) and some ground anise, but I don't have the amount right. I think another equal part of it would be too sweet, but I did about a half portion of it and that wasn't quite enough.
Anyway, it's been very fun and I recommend you try it if you like smoked meat.