I don't consider the recumbent bike much of a workout at all, for myself. I can get on one and cycle for about three minutes before I get a horrible burn from lactic acid buildup, but I never get winded, not matter how fast or slow I go or how heavy or light the reisitance.
I prefer using the regular "upright" workout bikes where you can stand up and pedal for an extra intensity boost. Unfortunately, I don't have a gym membership anymore so I can't use any bikes :-(
(In a few years when dh graduates from pharmacy school and is making a lot more money and we can afford a larger home, he says I can get some professional gym-quality exercise equipment- like bikes, a good elliptical trainer, or a versaclimber! Yeah!!)