What is the diffrence between Mister Vee Y&B and Mr. Vane?

Generally speaking, Mr. Vane is intended for smaller boats, and Y&B is intended for any size up to 12 meters. Other sizes of boats may work too but hey, this is a general answer.

The other mayor difference is in the mounting options.
Y&B standard offers an integrated solution for the vast majority of boats, and the flat configuration of Mr. Vane ads some options for even more situations, primarily on smaller boats.

For the best comparison, please refer to the Mister Vee Product Brochure from the download section.