We dock bow in in our current slip, it just works better for the angles and the neighbouring boat. Backing out is OK - we are tied to starboard, walk to port (minimally) so back out to port, stop and head down the fairway forward. The privacy is another issue.
However we've always owned boats that back well, and if in a tricky or new situation we traditionally would back in (esp when we had a folding prop) so we had reliable 'brakes'. Also the boat actually controlled just fine in reverse. I've seen other designs that would totally preclude that approach.
Now that we have a Max prop we've got good brakes whichever way we go in.. so it's mainly a decision based on the particular docking situation if we're away on a cruise. Whatever works is fine for us.
Otherwise puddin's rules are as good as any!
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"