Haze can be buffed out if it's from scratches. Just a pain to do, and often leaves distortion ripples in the viewing area.
The crack can be fixed with a plastic welder.
OR
can be fixed by sandwiching it between to acrylic pieces and using a two part blend to melt the seam chemically. It takes some practice though. This way is far cheaper, but usually ugly to look at.
It's a 40 gallon tank, so it's not really big. Go to petco when they are having their one $/per gallon sale and buy a glass one.
People got away from glass as it's heavy, but quite frankly it's one of the better materials out there for tanks, very hard to scratch. But less forgiving to abuse.
I have built several large custom tanks, including the ones that go into walls...acrylic is very forgiving to stresses but easily scratches and flexes under stress.
Given the option, I will always go with glass for anything under the 500 gallon range. They are just heavy as hell.