Seems like a deal, me personally wouldn’t just because I’m not a fan of acrylic.
600 is probably the least you’ll spend to get that monster up and running
The tank looks rough. Its hard to tell from the photo if it would clean up or not. $600 seems like a great deal but only if it will clean up and the acrylic isn't scratched up. Like tsharpe129 I'm not a fan of acrylic. I've been very succesful scratching glass. I can only imagine what I would do to acrylic
Personally, no, because like @exnisstech said, I'm adept at scratching glass, so me and acrylic would not get along. That being said, if that isn't a concern for you, at that price it is a steal. With a little elbow grease, you could clean it up and buff out any existing scratches. Best of luck, either way.