I really ought to read peoples "profiles" before opening my mouth.... if you've got a little 'un, I'm sure a bunked trailer will work.
However, you asked for an opinion and that's mine..I had a bunked trailer for my 4 metre Avon and it was a pain in the ass.. you needed to get the trailer quite deep before launch/recovery. True the friction on the bunks would hold it if the winch fails, but how important is that? If you are just relying on the winch strap, it might be a good idea to add a back up, whatever type of trailer..plenty of tails on this forum to attest to that..
I know a man who recovers off the beach.. and when I say off the beach, I mean he sticks his boat on the beach.. then fetches his trailer when the tide's gone out and winches his 225HP outboarded 23' sports fisher straight onto the trailer... try doing that with bunks...