Velocity and Mayflower both make top notch stuff. You will not go wrong with either company. I have been a user of their equipment since they first came on the open market in 2008.
I have run 15 different armor carriers since 2005. This includes PC, full coverage and hybrid rigs. Each has their place, but can cross over to a degree.
Definition time:
-plate carrier being narrowly defined as a carrier that only carries plates and backer armor.
-full coverage carrier accepts plates and full wrap soft armor that extends around the sides of the torso under the armpits.
-hybrid is loosely a plate carrier that can or does integrate detachable and separate cummerbund armor.
The Mayflower is a good full coverage carrier. It is what I a currently running as my patrol armor with VS13A armor and Velocities superb PBZ plates. It is comfortable, offers very good mobility, and integrates well with comms, mag and IFF. It may be overkill for just taking classes unless the classes require multiple gear lines and substantial coverage.
I also have had excellent results with the Crye JPC, and First Spear Strandhogg (SAPI cut). I have used both for callout rigs and am still using the JPC in that capacity.
The JPC is probably the best all purpose carrier going. It works well for classes, is expandable for various duty uses, provides the least disruption of shoulder mount when using long arms, and can by run slick for lower profile tasks.