All of these posts are helpful to me because I'm facing replacement of both knees...someday.
My orthopedic doc says I'll be able to ride a bike well after surgery, without restrictions. I'm putting the surgery off because I can still ride without pain; in fact, I can still get a good workout on an elliptical trainer without major discomfort.
I don't know about the bike mentioned in the OP, but I'd advise you to ride what you feel safe on. My wife isn't comfortable on skinny road bike tires these days, so she rides a mountain bike with the biggest non-knobby tires her wheels will accommodate; her big tires with plain tread provide a smooth, stable ride that works great on pavement, in grass, on bike paths, etc.. The low, sloping top tube makes it easy to get on and off. Her aluminum frame is lightweight, so its a pretty efficient ride. Give that approach some thought.
I firmly believe cycling is great exercise for our knees, before and after surgery. Good luck with your return to riding a bike, and let us know how you're doing.