The Pro 5 is one of the best built $3500 treads on the market. The only problem would be buying someone's top of the line model when they are known for their economy models...think Hyundai Genesis...if you don't mind the comparison, this is your machine.
Our hesitation would be paying $3500 for a Lifespan. If you can get over that, this is a very well built model. No one else is putting this kind of quality into this price point.