When there's not enough wind to plane or a wide formula board, the Serenity is just incredible.
Rig a smaller sail I've used a 9.0 Severne Gator (seemed kinda big and didn't seem to add much to the speed); 7.8 race sail, 7.5 Severne Glide (pretty good power and handling due to it's large draft and light weight); 7.5 m2 Sailworks Retro, 6.6 Sailworks Hucker and 5.5 m2 Sailworks Retro.
In all cases the Serenity was by far the fastest board on the water until the wind got steady at around 9-10 knots.
It just glides "serenely" along.
My skill level is probably considered "advanced" but I've had sailors with much less skill sail the Serenity and once the get balanced (takes a couple of tries for most sailors, regardless of skill level) they have no real problems sailing the Serenity upwind, reaching or broad reaching. Off the wind is a bit tricky and I'm still working on that as well as jibing.
Tacking is pretty easy, but it takes a while with a board this long.
Overall, when nearly all sailors are sitting on the beach complaining, you can be out on the water having a ball on the Serenity.
It handles alot more wind than most expect. It's pretty quick in more wind as well, but won't keep up with a formula or other wide boad once they are powered up and planing, but it planes along in it's own fashion with the nose well up out of the water and the bow wave moved back almost to the mast foot.
Hope this helps,