Two windy seasons each year out there one NW the other SE. In between each season its a gamble whether there will be anything.
In the off months its warm tropical wind and relatively gutless so while windguru shows plenty of green you will be hard pressed to launch.
Launching is sketchy depending on where you are. On Mahe the beaches are mostly very small with lots of trees around them. Doable but you want to know what you are doing.
On Mahe there are a couple of small reef breaks - near Grand Anse up near Victoria and the other down South near Anse Royal. I've never seen much on them. Bit of a break but nothing to wet yourself about.
You should also be good to surf at Beau Vallon but its not a surf break.
You cant hire anything out there unless you are in one of the resorts who mostly have SUPS and catamarans etc.
Its not a cheap place to go - deliberately. They limited tourism on the Islands years ago to max 120k per year and only let a handful of airlines come in. Thats recently been relaxed a bit in both respects but its not affected the cost of going there.
Nice place for relaxing and eating fish like KevinVermaak says but not a lot happens there. You can get really nice accom outside the resorts but either way its expensive.