i use them too for a few years now. once you get used to it you won't miss any more fish than normal and once a fish is hooked on a circle hook all the way, there's much less chance they come off.
like squatch said, make sure it's the inline type not offset and it has to be the right size for the bait you're using/target fish size. a 1/0 gamakatsu will work with med to large shiners and will hook up well with large perch up to nice sized pike. doesn't work every time but nothing does really. some people don't like them, but i can assure you once you get used to it, it works and it works well. I highly prefer them to regular hooks for tip ups.
if the fish is running hard, wait to touch the line (same i'd recommend for regular hooks too). if it slows down but is still moving, pinch the line down with your fingers (this will put the hook in the corner of the mouth most times) and IMMEDIATELY when you feel the fish start smoothly but firmly pulling the line in. Pull in as fast as the weight/fight of the fish will allow (again, same as regular hook). If the fish is not moving at all you'll need to slowly tighten up the line by slowly and smoothly pulling it in and then, same as before, immediately when feeling the fish start that smooth firm retrieve to make sure the hook goes all the way in.
I pretty much never gut hook fish unless i screw up with the above^ and i get cut off much much less by pickerel and pike without having to increase my leader test.
oh and make sure the circle hooks are needle sharp! if they are not maximum sticky get a new one. they are almost impossible to sharpen while maintaining full efficiency due to the design. you can't get away with a kind of sharp or pretty sharp hook point with circle hooks...at least i wouldn't chance it.
