Quantum is a nice unit, but is dependent on what you pool is made of. I just bought a Quantum in April and have been using it the last 2-3 weeks. Cleans really well and does come with the Ultra Filters. Below is the feedback I got from Maytronics:
Verify your Dolphin brushes are suitable for your pool type.
PVC brush - (PVC/liner, Tile, and Concrete pools)
Combined Brush - (Rough Ceramics, Stainless Steel, and Fiberglass pools)
Wonder Brush - (suitable for Smooth Ceramics and Stainless Steel pools)
The "PVC Brush" is the standard brush. The issue is that it gets trapped on slopes and can't turn. Does fine on flat surfaces, but will stir up the debris once in a while as the treads slip on the fiberglass surface.
Looks like you have a vinyl liner, so should be good with the standard brush. I would recommend getting the longest cable you can. Depending on how far your pool is from your outlet, you will want that extra cord. The cord between the power supply and the outlet is short, maybe 5'.