Accidents with the boom don't happen often, but usually the damage is much greater than a broken probe or ganked basket.
When the first C-17 for Hickam AFB was being delivered to the island a few years ago, the jet collided with their 135 tanker during a night AR with a bunch of maintainers/staff/public affairs onboard.... While the base commander was at the controls! Did some good damage to the boom, the tanker, and got a few dents. Still had the new car smell, though.
Another receiver unicorned the boom right off of it's 135 a year or two ago. There are pictures floating around of it.
The boom has a much faster offload rate with a heavy aircraft than the hose, and is far easier for a heavy pilot to make contact with, especially in turbulence. Refueling fighters with the boom is only marginally faster than refueling fighters on the centerline hose. Wing pod hoses, however, are faster than either, because of decreased cycle times. Pick your poison