I have owned the Tetragon 8 now for about 7 years. I believe it is now called the Tetragon 4. It has provided years of service and is still in good shape. It is easy to set up and take down. Only have had trouble with rain fly poles breaking as they have to be bent sharply to be placed in rain fly.
I have paddled the WS tarpon 160i for 4 years now and love it more than ever. It is comfortable for long trips and is very fast for a SOT. I tried several SINK kayaks and didn't like being confined into kayak. It is much cooler to paddle in summer as I can hang my feet in water and still be stable.
Overall this is a very good kayak. It is stable and comfortable to paddle. It is very maneuverable. Its drawback is it is rather slow and when paddled fast there is a lot of water noise from bow wake. I would rather not have molded foot rests. It is a good boat for just messing around a lake or small river. I did have fun surfing this kayak in 1-2ft waves at the beach but wouldn't attempt in large waves without a lot of practice.
I purchased a used Old Town 16 canoe 1986 model year-plastic. It was well used when I got it and 7 years later it still has a lot of years of use in it. This thing is a tank. Other than a little oil canning which it had when I purchased it. I'm not sure what I could do to damage it in a paddling setting. We use it in winter to pull behind tractor in snow loaded with kids.
Only bad thing is the weight. It is heavy and difficult to lift onto car so I use trailer to transport.
I had a sun velocity for a short time. I wasn't a huge fan of this kayak as I had a difficult time keeping a straight line. It's stable and roomy inside. At 13ft long it should have tracked better and perhaps could have been my early paddling technique. After this kayak I switched to SOT and never looked back. Most people like this kayak and I had no trouble selling it for a small profit.