Used them once for IM Switzerland and had an awesome experience. Ken Glah is a legendary figure at Kona and knows the needs of his IM customers better than they do. Everything is done for you and there are so many great touches. Definitely worth the money. I don't think I'd do another European race without their support. In fact I'm waiting on IM France registration until they determine if they are supporting the race next year.
As triathlon gains in popularity, there will be more athletes like me: never participated in competitive sports, minimal race experience, and only recently taken up endurance sports.
While training on a stationary bike could never fully substitute time on the road, there are many workouts you can perform to work on a piece of your cycling.