I didn't replace my windshield just because of the HUD, and I can see it just fine, nice and sharp too.
I'm thinking of getting a new one just because mine is pitted so bad, that I can't see if the glare hits it just right. Safelite only wants $30 more for HUD windshield, so if I got a new one, I'd get the HUD since it's such a small difference.
Jesse