What kind of experience is it to come out of a coma?

Depends: Hard to say if it's not you coming out of it. Coma is a state of asleep-like unresponsiveness. Recovery depends on cause, duration & severity of coma. Outcome can range from normal (just like waking up) to a permanent vegetative state i.e. awake-like unresponsiveness & lack of awareness of environment. Some things e.g. stroke in certain areas of the pons can cause irreversible coma.