I've owned a Thresher 140 for a little over a year. I've launched it off the beach on the west coast of Washington state a few times, I've had in it Puget Sound, half a dozen rivers, and a bunch of lakes, big and small.
Before the Thresher 140 I owned a Tarpon 120 for many years. I loved that kayak, but I sold it because I needed to slim down my kayak collection to only a couple (down from about 12, although most were sit-inside touring.)
The reason I kept the Thresher over the others is because it loves to climb over everything. This boat has a lot of rocker. Where the Tarpon mostly wanted to pierce through waves, the Thresher will climb and even surf a bit. It feels safer and more stable.
For this it sacrifices some speed. The Tarpon feels like it glides, where the Thresher plows the water more. I'd prefer the Tarpon if I were mostly out on calmer days, or had more money and space for kayaks.
If you're interested in the Thresher 140 definitely try and test paddle the Tarpon series also. They have different gear accommodations, but after paddling them both you may find that those don't matter quite as much.
All in all it's a well built kayak, designed with a purpose. If your reason to buy this kayak doesn't include beach launching or some rough big waters, I'd say there are better options.
For the mission it was built, I'd give it 5/5. Although I don't like that the blow-molded Flex Pod OS doesn't have a gasket. If you flip or practice re-entries that thing fills with water.
