Sorry for replying without really reading the other replies, but I wanted to chime in with my pellet smoker experience.
I have a Rec Tec and I HIGHLY recommend it! The pellet technology in general is great, regardless of brand, because you can just set it and forget it. No need to baby it by watching and checking temps, etc. I realize there are some who enjoy doing that part of smoking, so it might not be for everyone. But the ease of it is what appealed to me.
As far as why I chose the Rec Tec:
HEAVY gauge stainless steel used throughout, making it an absolute tank. The thickness of the grill is what will set it apart from others, more durable and will last longer.
6 year warranty and some of the best customer service/support around! They include their cards with each smoker and encourage you to call/text them with ANY questions or concerns. I have used this many times when checking on certain cuts of meat and how long to smoke something or get hints, always a reply within an hour. Had a tear in my cover, asked them about it, without asking they sent out a new one.
They now make a mini along with their large 680, I hear it is great for camping.
There are also all kinds of mods being made or added to pellet smokers from all brands, if you get one or have one, be sure to check out all the different message boards, Facebook pages, etc for all types of hints, tricks, recipes. Some mods provide more smoke, or the new thing now is a pizza oven made by Green Mountain which heats up to over 900 degrees and cooks pizzas in 2-3 minutes.
Bottom line is these are fun to have and produce delicious food. My advice is to be sure to check out all specs to be sure you're getting the most bang for your buck. I'm happy with the Rec Tec. (Plus it has awesome chrome bull horns for handles!)