Each machine has its strengths and weaknesses. I find that stationary bikes tend to get really uncomfortable after awhile, too. My posture isn't the best and I

Each machine has its strengths and weaknesses. I find that stationary bikes tend to get really uncomfortable after awhile, too. My posture isn't the best and I feel like I suffer on a bike because of the hunching I feel like I have to do in order to grip the bars in front of me. It's also worth mentioning that a mediocre seat can definitely be painful after a period of time. In the bike's defense: as a runner, spinning on the bike is an absolutely awesome to maintain cardio-fitness after a running injury.