I think the comparison of Grenke to Saberhagen is pretty good. I don't know if anyone will ever be another Maddux, but Zach is in that mold of "pin-point control, changing speed, reach back and grab a 96 mph fast ball when needed" kind of pitcher.
I think he will be around for a long time. Bonderman, on the other hand, is a blown elbow waiting to happen. I'm planning to grab him in our auction next spring and hope he starts the season well so I can trade him high, right before the injury. I love it when that happens!