Mostly very safe. Provided the surgeon, pediatrician, obstetrician or mohel is well trained and careful. I believe plastibell method, where the redundant foreskin is tied off over a small plastic ring is the safest because risk of bleeding is very slight.. Correct size plastibell ring must be selected and a frenular bleed should be cauterized.(check google.Com). Clamp method usually safe, but risk of bleed more.
Very. The only question for non jewish people is -------why? It has become a routine, based on the most absurd concepts. Males were provided with a foreskin. The only thing required when older is good hygiene.