I don't subscribe to Max but I have used it at my brother-in-law's place. Here are my comments.
Picture quality and sound quality seem fine. Stereo and Dolby ProLogic only, which isn't awful. No Dolby Digital 5.1. The fact that SPDIF boxes are coming is a good sign on this front. To be fair, not much on Access Communications (or presumably Shaw) is in 5.1 yet so the advantage is fairly small.
Channel changing is pretty zippy, not as fast as with my 6412 box, but faster than my 1000 or 2000. There is no annoying pause-freeze as with the 6412 though.
I haven't noticed any image blocking problems, but I haven't watched enough to know.
You can only have two decoder boxes which is rather limiting. It'd be great for a single person or married couple, but a family with children might want more than two TVs. You can probably jury rig some sort of setup where you can intercept the network output of one box (the signal travels over Ethernet cable through a switch), but you shouldn't have to.
No HDTV yet. I'm sure it's coming, but Access has it now. Granted, at least in the non-rebuilt areas of Regina, Access has some bandwidth issues that create dropout. Then again, I have three cable boxes and the fastest consumer Internet package, so I'm pushing the bandwidth as far as is possible pretty much.
Max isn't for me but it certainly should be on the table of many consumers.