Which ProForm treadmill is the best?

ProForm treadmills are unique in their way. The best five ProForm Treadmills are

ProForm SMART Pro 5000
ProForm SMART Pro 2000
ProForm 705 CST

ProForm SMART Pro 9000
and the ProForm Carbon T10

Proform-600i-performance

It is worthy of note that this collection comes iFit Coach technology,  even though they each feature some differences in durability, price, and performance.