I'm using a Speedhub on a road bike, not an MTB,
but I think it's worth the money, and I would buy another.
One control gets you all the gears in sequence, you can
shift whether pedaling or not, the wheel has no dish,
indexing doesn't depend on getting cable (or any other)
adjustment right, and the hub is built to last.

In the higher gears, the drivetrain is quiet. In lower gears, not.

Tom Ace