EF to FD adapter types

I have some great FD lenses from my film AE-1, AE-1P, and A-1 days that I cannot bear to part with. A quick check of ebay yields at least a dozen FD lens to EF camera adapters, which seem to fall into two groups: no glass macro, and with glass "focus to infinity". Surely you will lose a couple of f-stops with the glass. If someone can comment on their personal experience with any given brand or type I would appreciate it.
Finn