I have an 8-speed Shimano Alfine hub on my GT Eightball.
I love the clean look and the shifter is crisp and reliable in practice. Its tough enough to run on hardpack & gravel trails as well as pavement around here.
No problems with it. An IGH drivetrain on a bike is as maintainance-free as you can get.
Whatever IGH you decide to get, it would last you a lifetime. Heck, people today still ride 50 and 60 year old English 3 speed IGH bikes without incident.
Good luck.