I've had the new foil board a few weeks and been out half a dozen times with sails ranging from 9m to 5.5m, using the Starboard Racefoil and the GT. I'm moving from a Starboard Foil 147, modified with backfoot wings so this brief review is really a comparison between the two boards. Note that installing backfoot wings improved the Foil 147's racing performance substantially.
Physically the Foil 177 is a beast of a board, being thicker and wider at the tail, although the foil 147 has a marginally bigger wide point (95cm vs 91cm). Both boards weigh about the same (note that is with the wings on the 147) - both made from Carbon Reflex.
On the Foil 177 the foot straps are further from the centreline of the board (and closer to the rails), particularly the front footstraps, but about the same distance apart. The chicken straps are further forward. The mast track is located further forward from the foil mast and overall the Foil 177 is shorter.

The Foil 147 was developed from the Ultrasonic 147 and as such works OK as a big slalom board, but I have doubts that the Foil 177 would work as a windsurfer - it just doesn't look right! I probably will never try it with a fin so that is not an issue.
On the water the board feels very stable with a LOT of real estate to put your feet on. The takeoff seems to be very easy with very little sign of "stickyness", probably helped by cutaways that are chamfered up. The footstrap position seems perfect for me - easy to get into and comfortable. The on-the-rail straps will feel very familiar to formula board riders. The chicken straps are also very well placed for downwind blasting, creating a stable body position to control lift but still harness good power from the sail.

Although the small sails work fine it was clear that the board is more designed for bigger sails where the outboard stance can extract good power. Rolling the board to windward going upwind is very easy and also keeping the board flat going downwind is good, although I found it difficult with the back foot in the outer straps - any loss of power due to oversheeting or lulls causes the board to fall to your heels which quickly rounds the board. It is much easier to use your toe and heel pressure to keep things flat when in the chicken strap.
I was initially worried that the wide nose would get blown around in the wind but this does not seem to happen. The nose feels close to the mast foot so any sudden change in nose lift is deadened by the short lever arm. I am particularly impressed by the touchdown performance of the board. The high nose rocker and prominent vee in the start of the nose rocker seems enough to enable an effective bounce back from a touchdown - no sticky splash here! The board has sharp boxy rails the full length and these work very well when touching down whilst railed over going upwind, helped no doubt by the parallel rails. The inevitable slow down when touching the water seems to be much reduced.

Gybing the board seems well mannered but tacking is slow no doubt due to the wide tail - I suppose I'll have to get a lot better at foil tacking!!
Overall I'm impressed by this board - clearly designed for racing but very good at just cruising around. Initially I was going to keep hold of the Foil 147 (which I really like) but there doesn't seem any sound reason for doing that!
I'll do some more posting on how this board goes with the soon-to-be-released Starboard RacePro foil - can't wait!