they are both really nice boards, but very different.I have a Race14x25 and i,m right now a 94kg

and I love the board on flat water.
Its very fast in that kind of conditions, imo faster as an 2015 Falcon14x24, but the big downtrade is that it seems that in side-chop the nose makes up his own mind and steers quicker away as most boards I know. Starboard marketed the Race as an allround raceboard, but imo its rather dedicated flatwater.In the beginning it feels a bit unstable and rolling when standing still or going slow, but it needs a lot to really tip over.At speed it stabilizes very quickly, the nose raises a bit and it cuts through chop. Sometimes it dives under but it doesnt slow the board down, a bit like an torpedo. :)I paddled only one Ace, that one was great in rough water, but not as fast and trully silence gliding/slicing through the water as the Race.
If you are in a downwind area the Ace is hard to beat.