I bought a Nordictrack Commercial 1750 last October. The initial walking deck (ie the piece inside the belt that you run on) made it a little over 500 miles over 5 months, and it developed severe heat stress and fractured from the top to about halfway down the deck. It took Nordictrack's parent company, ICON fitness, 3 months to get me a new deck and get a technician out to repair/replace it. They fixed it in June, and I ran 0.3 miles on it to make sure it was working properly and then didn't use it again until August because the temperatures were warm outside and I mostly just have it for winter use. I did 2 easy runs on it in August totaling 15.9 additional miles, and the new walking deck broke in half from the front almost completely to the back during the second run. The technician repaired it today and confirmed that there is no frame damage, and everything is working correctly. The decks are just really poorly made. I'm not an elite runner by any means, but I'm at least a ~150 pound dude that isn't exactly putting a ton of stress on the deck by running easy runs at 7:30 pace. I cannot fathom how they can get away with building treadmills with components this bad. Notably, they didn't package my 3rd walking deck very well, and all 4 corners were pretty dinged up on arrival. Hopefully that won't cause this one to also fail immediately.
I'm primarily posting this because I think most people on here considering buying a treadmill ought to be really wary of what they're buying. My experience has been very negative. If I had to buy again, I wouldn't really consider anything under $4000, which is about where legitimate commercial grade machines start. These $3000 and under treadmills are apparently pretty universally built with walking decks made from little more than particle board. If you're at all serious about running and want to put your treadmill under the stress of doing runs of more than 2 or 3 miles at a time, you would not be serving yourself well by buying something like what I got.