This morning I had limited time at the gym so I got on the evil arc trainer and had a helluva workout. I literally didn't know if I could finish 30 minutes. I usually do 40 or 45 on the treadmill on an incline or on the elliptical with moderate resistance, and I think I'm getting a decent workout doing that. However, I think my 30 minutes on the arc trainer working hard was actually a better workout. I honestly don't know if I could work out that hard every day at my current fitness level (which has gotten remarkably better but still isn't great).
What do you guys do? Harder, shorter workouts or longer, moderate workouts? What do you think are better, and when have you gotten your best results?