Mostly good. These things have oodles of space, and a giant cargo capacity even with all seats filled. The automatic will be a DSG dual-clutch - very good. I`ve only ever had them (from Avis, though) in well-equipped form including niceties like adaptive cruise control and navigation. They always had the torquey 2.0 TDI (150hp) which combined good fuel economy with adequate power.
If you don't need the third row and return to the same location, it might be possible to remove the seats it and leave them at the agency. The seats don't fold flat and take up space if not used.
Not so good: "Maxi" means long wheelbase, which can be a bit unwieldy to park and maneuver around tight places. Turning circle is more than 12m, and total length is approaching 5m.
Also, the van origins are showing in that the suspension isn't as sophisticated as in car-based MPVs - there's a live axle in the back. And the windows in the second row (in the sliding doors) don't roll down, VW just offers small sliding windows as an option. Of the three Caddys I rented two had the sliding windows and one didn't
Overall, I was very happy and would go for one every time.