With the other respondants here, I agree that damage to the aircraft / avionics etc., is at worst minimal. In my experience a few pin holes and a lost ADF antenna were the worst cases that I've experienced.
An important aspect to flight safety is the effect upon pilot vision in the event of a strike in the proximity of the cockpit. In one strike close to the nose, both of us were blinded for up to 3 to 4 minutes. Thank God that the Auto-Pilot was engaged, and cockpit lighting was at maximum intensity. They don't call it the Thunderstorm Light for nothing.
Regards,
Old Smokey