The acrylic is only on the unheated bed. I hope no one is ordering those, the $50 saved will buy a lot of frustration with warping. I would consider printing only PLA on one of those. The heated beds are aluminum.
The glass is mostly people printing PLA on heated beds. PLA will stick to unheated acrylic, but acrylic tends to warp (unless its 10mm thick like the Solidoodle bed). Glass won't warp, but PLA won't stick to it unless it's hot. It also won't stick to Kapton unless the Kapton is heated as well. I don't think ABS will stick to glass at all unless you spread ABS glue on it first.
If you decide to stick with PLA, you could put a piece of glass on the aluminum and hold it down with binder clips. You would have to take it off to get at the leveling screws however.