this .....

go to the areas you intend to sail at and find out what class is mainly sailed in the area, there will be reasons why a particular class of cat is favoured over others for its suitability.
find out those reasons and you'll have a better understanding of the areas sailing conditions


2ndly...
if you have issues with your new toy then the locals will have a good knowledge base with which they can assist you to fix your boat or style of sailing to better suit, if however you buy something that's not normally seen in the area then you'll find you'll be largely 'on your own' when it comes to issues.


finally ..... and something that few consider ....
resale of the boat once you decide to upgrade / move-on etc
You'll have more chance of selling a boat in an area where a "fleet" exists for the 2 above reasons, very few would take the risk of going to an entirely new class that's not well known in the area..... the exception is the newbie guy who'll be making the same mistake you did by buying the wrong class for the area