I have owned an S2 7.9 for ten years - keep it at the Sandusky Sailing Club, where this year we will have three of them. Here are a few comments based on what has been written so far. (1) If your wife is like mine, she will NEVER be comfortable in 3 to 5 foot waves. And around 25 kts is when expensive things start to tear & break. For those reasons I don't go out if I know it's going to blow about 22 or more. (2) Buy a 7.9 with an outboard. The inboard's are much harder to sell, and have had reliability issues (parts not available) (3) Check out the class assoc web page. for things to inspect carefully before you buy (like water intrusion around the coaming winches
, stantions (sp?) and mast step). These may not be deal breakers (my boat, # 445, had all of them), but should affect what you pay. Get a survey for sure. (4) I like the interior liner - it helps to dampen sound, and can be used to hold velcro stuff. (5) the dagger board weighs 600 lbs. (6) I love how the boat sails - I cruise it over to Canada regularly, and do some racing. It's way fun to just blow away larger boats. It will do 6.5 kts routinely, and over 7 in the right (broad reach) conditions. (7) The 7.9s hold their value well. If you pay $ 17K (for a good one) you should be able to get most or all of that back when you sell it.
Let me know if you have any questions, and feel free to stop by SSC for a 7.9 sail in the spring if you are in the area.