Although I prefer the War Frigate overall, I still like the War Galleon and War Sloop. It all depends on what you plan to do.
-The War Frigate can take more of a beating for close combat and the front cannons are very nice to have
-The War Galleon has more storage and broadsides but in my opinion not recommended for close battles as the hull gives out faster
-The War Sloop will zip you around faster and still has decent firepower and hull
I waited until I had the 60,000 and purchased the War Frigate first as I figured it would be the biggest bang for the buck. Then I purchased the War Sloop and last but by far not least the War Galleon. I use all three of them on a regular basis. My guild likes the cannon arrangement of the Frigate but loves the large hauls with the Galleon.