Recommended Treadmill

Want to purchase treadmill to do some marathon training on it. Any good recommendation ? Looking for commercial one with Zwift. How about curved treadmill ? Also, anyone using curved treadmill for long run ?

Thanks

Id say any relatively modern treadmill would be fine. My personal preference is a wider deck and strong fans to keep me cool. Some sort of shock absorption technology is great to reduce strain. The treadmill at my local gym is probably 8-10 years old and works without issue. For Zwift I use Garmin Forerunner 245 which is generally 100-300m incorrect for every 6km I run but I consider that “good enough”.