I own a Yoder YS480 http://www.yodersmokers.com/pellet-grills.html, and I have used a Green Mountain Grill http://greenmountaingrills.com/. I have a friend that has a MAK grill https://www.makgrills.com/.
The green mountain grill was great, but from the time I played around with one to the time I was going to sit down and order one the company had since shifted production to China and their quality control took a big hit. Traeger grills were the same way. Traeger's are sold at Sams (or Costco? one of the bulk stores) via live demos and are a somewhat popular non-professional grade pellet grill, but they are made in China, despite what the company reps will tell you. I've seen them not even be welded together right.
For me it came down to the MAK or the Yoder. Both are American made and high quality. Both have electronic temperature control/feeding like you'd expect them to. They both cook evenly. It came down to not only price but what deals the company had at the time I ordered it. MAK was a $1500 grill and didn't come with much in the way of accessories, but they did have a wide range of different racks/griddles/whatever you'd want to help you cook specific foods on the grill. The Yoder didn't have as many little unitasker accessories but was $1100 (I think) at the time I bought it, but they were willing to throw in a couple bags of pellets and discounted the grill grates I bought as an extra.
Cooking is super easy on them. You turn it on, set the temp you want to cook at, and it automatically feeds pellets from the hopper into grill. They have a small igniter in the bottom corner of the grill the fires the pellets. I've found that I get better results if I prime the igniter first, as in take a small handful of pellets out of the hopper and set them on the igniter to jump start the thing. Mine I can set to 400 and it goes from cold to temp in about 5-6 minutes if it's not freezing cold outside. The colder it is the longer it will take to come up to temp by a few minutes and it will burn more pellets staying there. Pellets are thankfully cheap though unless you go buy the boutique ones. You can buy wood pellets from home depot and the like really freaking cheap but DO NOT DO IT. As tempting as it may be, they are not food grade wood pellets. Those things are made from ground and pressed anything. Old trim, wood panels, old cabinets, anything thrown out really. They can contain paint and other chemicals you do not want consuming. Not good eats.
Also don't be tempted to buy the biggest grill you can afford. The differences between the starter models and the more expensive ones are a lot of the time just square inches of cooking space. I bought the smaller Yoder and the thing is still pretty large on the inside. I can easily fit enough burgers/chicken breasts to feed an army on the thing and still have room to spare. If you cook a lot of larger items like whole chickens and several whole racks of ribs or whatnot, you might consider going with a bigger grill, but I have plenty of room for anything I've ever wanted to smoke/grill on this thing.
There are good YouTube videos of both in action and demonstrations of how they work. I've owned my Yoder for about... 3-4 years now and it works great. Here lately the internal thermometer has been a little wonky but I probably just need to give the thing a good scrubbing. Like I said both MAK and Yoder make an excellent grill. MAK is probably the better grill to be honest, but you're going to pay for it. The thing is just a beast.
As an afterthought, if you order one online and have them freight it to you, make sure you have help unloading it. The truck that arrived to deliver mine didn't have a lift gate, and my "small" Yoder is almost 300 lbs. These things aren't made out of sheet metal.