All in all I would say no to using it either. I didn't have the coral problems and secondary infection issues (got lucky??) but as I said it DID kill my mandarin. Even if you use it and the problem "goes away," it won't be effective as a treatment against later attacks. There is really only ONE completely reef-safe and 100% effective way to treat ich in a reef display:
Remove all fish to a secondary hospital tank, and treat with copper or hypo
Allow display tank to remain fallow (just coral and inverts) for 2 months.
I may be wrong about the time for leaving the tank empty. Do some research and check on that. It's a heck of a solution and very labor / time intensive, but if there's ich in the display tank, the only way it's coming out is if you remove the host animals and allow the parasites to die out....including encysted eggs.
Naturally, your best bet is prevention. QT is your friend!