....However, I'm concerned about scratching with acrylic.
Does anyone have an acrylic aquarium and could you tell me just how easy it is to scratch? Can I use a mag-float?
I've owned several for Reef and Fresh. My current 40 is Acrylic. Acrylic will scratch easier than glass. But, glass isn't immune either. Seldom do you find a used glass tank with out scratches.
It's more a matter of how careful you are willing to be when you work in your tank. If you know you are a clumsy oaf, then do not get acrylic. If you approach the tank maintenance with they inner peace of a Buddhist monk you will not have problems.
Also, unlike reef tanks we tend not to use sharp edged hardscape like live rock.
I don't recommend mag floats for any tank.