We are on our second treadmill, my wife is a serious runner and will do two to three 5k runs a week.
The current one is branded Roger Black and is going very strong. It is nicely made and functional.
The last one wasn't Roger Black, I can't remember who made it,. It wore out the motor (I replaced it) then the circuit board fried,. And I couldn't find a replacement.
I would suggest you don't need to spend mega bucks, but the cheaper it is the more likely you'll need to repair/fix it.