I've sailed the 17 for a number of years and just started sailing the 14 a little bit this year. I'm 6'-3" a little over 200 lbs.
The 14 is actually a pretty fun boat in a lot of ways. Very simple design that is quick to rig and easy to move around on shore. It is also a lot of fun when the wind is up because the boat is pretty much always on the edge of capsizing one way or the other. When you're out on the wire, it feels pretty much just like any other Hobie - fun to fly a hull. On a powered up beam reach it may not be as fast as other boats, but it still feels fast - the "go kart" factor. I find that racing is not nearly as much fun as bigger boats. It's very tough to get in the groove upwind and downwind is a parade. Lighter sailors definitely have an advantage as well.
The 17 is a great boat. It has a much more powerful rig than the 14 which means you will get out on the wire sooner. It is also quite a bit faster than tbe 14 on all points of sail. It is a pretty simple design as well and really doesn't take too long to rig either. If you keep the rudders on the boat, you could probably be fully rigged in about 20 to 25 minutes. Optimum weight for the 17 is about 170 to 180 lbs but the boat can handle more weight than that including a crew if you're fun sailing. The 17 is not as beach friendly as the 14 because of the centerboards you want to avoid dragging it over sand or pebbles because these will jam the centerboards. Its also about 100 lbs heavier than the 14, so beach wheels are pretty much mandatory.
Inspecting the 17, the main things to look for are: soft spots on the hulls. Cracks on the inside of the hull starting around the front crossbar and running forward towards the bow. Cracks in the front and rear crossbars. These can occur at the hole for the mast step. They can also form at the rivets near the inboard side of the hulls under the crossbar and wrap around the bottom of the crossbar. Corrosion holes in the aluminum wing tubing. Leaks in the wing sockets in the hulls. Broken hooks on the centerboards or excessive wear on the leading edge of the centerboards. Delamination of the mylar sailcloth on older sails.