Not that many go bad, but more than Interstate, Exide, Sears, etc.
From Moparts.org BBS: many complaints of short service life (less than 1 year), but the real problem is that (in those posts) the dealer tells you to send it back to Optima yourself, and Optima tells you the dealer must warranty it. Therefore warranty = worthless.
This may be old information, but it was pretty bad at the time - like getting a replacement that lasted 1 month. 1 bad in a row doesn't prove anything, 2 bad in a row: no excuse.
Special charger = "there was nothing wrong with it, you broke it".
Just personal: I don't buy anything, no matter how good it is, when the manufacturer stiffs you.