Thanks for the feedback. I hadn't heard about the porpoising issue before now. Granted, I haven't found a ton on this boat model, but what I had has been very good. I'm going to try and get a test ride, though it'll be a cold one.
I have a mid-size SUV so tow weight is a factor at the moment. I can't swing buying a bigger tow vehicle and a boat, so I'm working on using what I have so I can get on the water now rather than waiting a few more years.
I have found a third option in the same price range and not too far away. A 2008 Nitro Z6 w/90 hp Mercury. Is that too under-powered for the boat? Keep in mind, I don't do tourney's and I don't need to run 60+ mph (although it'd be fun). Says it has 150 hours on it. It seems to be in a similar weight range as the Avalanche, just a little shorter and less powerful motors.