The black one lasted two seasons but it was worth the slightly higher price because the FC loss was nil when it was on, compare to a daily loss of 1fc with the basic, when it was on.
If there was 3-5 days of no swimming for whatever reason, and the cover was on, I wouldn't need to add chlorine at all. That was a good deal to me.
As for problems with using a cover - I've used a cover as long as I've had the pool. Never had any issues related to algae forming, etc, as long as I've maintained the proper FC it just wasn't an issue. The PH would drift down slightly however.
I have gone on 11 day vacations, shocked and covered and come home to a FC above my min, with no chlorine additions. Maybe I've been lucky, IDK, but I've read alot of problems from people who blame their cover - I just haven't experienced that.