Alright, I bought my kayak. here's some quick thoughts to the process:
I went to the dealer fully expecting to buy an OK Prowler 15 for a decently discounted price - thoughts being it's fast, a good fisher, lighter than the Tarpons. What could go wrong? Went into their warehouse to see how well I could lift it (it had a rudder) - way too back heavy, which made it very awkward to lift. Didn't even bother checking out the Tarpon 160. So it came down to the Prowler 13 and the Tarpon 140, both with rudders. Surprisingly, they were about equal to lift. Although the Tarpon was heavier, it was more equally balanced. Onto the water...
Performance-wise, the Prowler got up to speed better and had decent glide. It had a little side-to-side motion with my strokes, even with the rudder down. The Tarpon took a little more to get going, and was a little "heavier" feeling to paddle, although faster. Straight as an arrow, no side-to-side with or without rudder. Tons of glide. Well behaved without the rudder.
So, I felt through all that both boats were equal. I came down to ergonomics and the little things. The Prowler's seat was a joke. The hatches are rubbermaid-type. very difficult to get off in the water and the small hatch took on water. The rudder system was difficult to pull up and down and to do so, you had to tug on bare polypropylene rope, which doesn't feel none too good. The combination of footwells and rudder pegs was a bit annoying, and the cockpit was too busy.
The Tarpon's seat was very supportive, has nice easy adjustments for back height and thigh support, and locks down for when you mount it upside down on your car. The rudder was easy to deploy and you grab nice soft rubber toggles to do so. Plenty of room in the cockpit, no footwells to bother rudder operation.
Tarpon 140 it was. I felt it would've been fine without a rudder based on the handling, but i figured there would be times that I wished I had it, so I got one.