I've had Baja Bound insurance for more that ten years now with thousands of miles logged in Baja....Fortunately, I've only had one fender bender in that time where I had to call them. That one incident was by far the smoothest process I've been through, even more so than dealing with insurance in the States.
I would highly recommend Baja Bound to anyone looking to travel in Baja. Geoff and his people are amongst the finest people you'll ever deal with.