I've got a Trek 6000 that I really enjoy. I chose it over the Marlin myself. I found the Dart 3 nicer than the Suntour on the Marlin and the sizing on the Marlin didn't feel right to me. The 6000 "felt right." Also, the shifting on the X5 was a touch nicer.

Also, I'd imagine the 6000 may be small for you. I'm about 5'8"-5'9" and ride a 17.5 and it feels pretty damn good to me.