There are only 2 current models: Pool Buster Max and Pool Buster Max CG. The CG model (stands for Commercial Grade) has 30% more suction and recharges in 2 hours and comes with the fine filter. The regular Max normally recharges in 8 hours.

The CG is about $50 more on the web, with the fine filter costing $25, it might be worth it.

There is a tip on the PB web site about using the wheels (instead of the brushes) for better suction. I have used only the wheels so far (on a vinyl IG), so I can't comment on the difference. The limiting factor for us has been the (relatively) small size of the pickup bag. We have had no problem with the power or charge length.

So, I think either would work fine. The regular Max is much easier to find, I only found 3 or 4 sites that sell the CG model.