About 5 years ago, I purchased the Smooth 5.25, which is basically an earlier model of the same treadmill Woot is selling here. Overall, I have been happy with the treadmill and have had zero problems with it to date. The treadmill is solid and substantial, which is more than I can say for some of the cheaper models. This is important because you don't want the treadmill to feel unstable while you're using it!. The only maintenance I have had to do is to lubricate the belt, which is somewhat of a pain, but not difficult to do.
When researching treadmills, I referred to the Treadmill Doctor website to evaluate different brands and models. Since they also sell parts, It's a good resource for seeing what type of maintenance and repair costs you might face down the road as well. Here's their review of the Smooth 5.65:
I am not a small guy (210 lbs) and have had no problems jogging on our treadmill at a 6 - 7 mph speed for 5 miles at a time. The model I own has a 275 lb max weight, so I'm fairly close to the max weight limit, but that hasn't seemed to negatively affect the durability or life of the treadmill to date.
Overall, I'd recommend the Smooth brand if you're in the market for a good, moderate-use treadmill.