I looked at all these boats at one time. The Sonic 260 Prowler is a great built boat...very very solid. Excellent rough water boat. I saw the design of this boat happening when I went to the Sonic factory a few times back in 1997. I came very close to buying this boat but it would not be out for sale when I was ready to buy. The Checkmate is more of a lake boat and the Velocity is very lightweight thin coring and stringer and runs on a huge flat pad and this pad runs well up towards the bow. That does not make for a great rough water boat and it tends to shoot the bow up when going into a wave. You will have the pay a lot of attention when driving the Velocity at speed. I am biased because I have seen way too many Velocity boats delaminate and break apart. However I love the Velocity looks and deep cockpit. Out of the 3 boats you listed the Veocity will be the fastest in smooth water.