I agree that you need a good quality trainer or spin bike. My trainer is a Kurt Kinetic Road Machine. It feels like you are riding on the road. The spin bike doesn't not feel as natural as my kurt. The resistance on the Kurt is equal to putting your bike in the hardest gear and riding on a 2% grade. Yes you get resistance but not as much as I want to simulate hill climbing. I want to be able to make the pedals extremely difficult to turn.

However, I have gotten my heart up higher on the Kurt than I have on the spin bike but I think it has more to do with the instructor and how much I am pushing myself. The Spinerval DVDs are excellent and if you follow them, you will get your ass kicked on either a trainer or spin bike.