@airsail HA850 is my go-to for everything from light wind to overhead swell. Super well balanced, low stall speed, turns well, good glide, good pumpability, accelerates well to connect bumps. I tried the SF930/S215 in shoulder to overhead swell in 30 knts and was surprised by how well it behaved. No excessive front foot pressure despite dropping straight down the swells, very very difficult to overfoil and breach, very forgiven in that respect, turned well, very carvy. However, it wasn't fast enough to stay with the fast river swell or connect with them when pumping, that's where the HA850 shines. (or HA650).
But I was surprised by how easy the SF930 was to ride even in big conditions. It's like having ABS, traction control and a bunch of other driver aids on, it's very forgiving.
So my feeling is that the SF930 is a good wing for below waist high fast river swell or slower shoulder/overhead ocean swell if winging or proning.