i had a friend that would die before he said regrinds were bad, yes they CAN be bad for valve train, but NOT always, if done right they make alot more power, cost alot less than full cams, and are perfectly safe to run. all they do is grind ur stock cams, to give u more aggresive cams, therefore making more power. i think they are good but only if done right.
Example, my friend had a 1990 Civic Si, with a ZC, with i/h/e. ran 15.1 fully gutted. Took his cams to Colt Cams, got them ground, and after that ran a 14.6. he drove on them for a year before he sold the engine and got a b18c5, and never had a problem