We do a lot of camping while we travel, some KOA some not, and this was easily one of the best campsites we've ever stayed at! Great, spacious, well-kept grounds, a clean swimming pool, individual shower rooms (as well as typically stalls), and very friendly, helpful staff. Very close to the city/highway, yet felt secluded enough to still feel like camping. Other than the mosquitos (which can't really be helped), we loved it! Would absolutely stay again.
Windy Point Park definitely lives up to its name! Very windy, but right on the lake so somewhat to be expected. No beach access, but several steps leading straight into the depths of the lake to swim. Also saw some people scuba diving, so that's neat.
A negative to this campsite is it's very primitive. Only open air, rinse-off showers and porta potties. No sinks or electric hook ups anywhere on-site that we could find. It's a smaller camp ground, so could easily be a bit crowded on a weekend as well.
They have wagons to haul your stuff from the parking lot to the campsite, in order to keep the grounds untouched by vehicle traffic.
15 min winding drive to the nearest town. 5 minute drive to The Oasis, which I highly recommend at least checking out while you're there. Even if you don't want to spend the time or money to eat there, the bar is an easy, but still beautiful alternative.
Overall, I would recommend for a day trip hanging out by Lake Travis, but not sure I would stay the night again.