I have a 2011 and I bought a 2019 this past year. The 2011 is a great kayak, but the 2019 is better in many ways.
It is a faster hull, but it is a wetter hull. The pre-2019 hull shape would float over waves instead of cutting through them. I definitely prefer the quieter faster hull of the 2019. One other thing is that the 2011 sits a bit nose up and the 2019 sits much more level on the water - at least when I have both of them loaded. The 2011 does have a larger front hatch.
I never had any complaints about my 2011 seat except that I would have to yank on the straps a few times a day to retighten it. However, that is like saying hamburger is as good as it gets because you have never had a prime steak

The 2019 seat is really nice and being able to adjust it up and down is sweet. For sturgeon I keep it low and for bass I keep it high.
The cockpit layout and the hatch on the 2019 are way nicer than the 2011. The cutouts on the sides and the H-bars are really nice and useful. Plush the rubber side pockets are great (but you could probably add those to a 2011. The rectangular hatch and bucket seem to seal better and more easily.
The rear cockpit again with the H-tracks has proven to be really great for me. I mount my transducer on an arm from on one side and my flag on the other. You could add tracks to the 2011 so this may not be as big of a deal, but once again the cutout areas are great for organizing gear. Nice to have stuff but not have to have.
I thought the reverse on the Mirage drive was a stupid gimmick before I used it. Man that is nice to have. I use it to gain leverage when fighting big fish like sturgeon and for holding position in current or wind. It is pretty good for that but a little harder to keep the kayak straight, but still nice to have.
The turning radius and response of the 2019 is much better, but you do have to be careful about the rudder since it is stored in a vulnerable position. At first I was a little worried about this but overall it has not been an issue.
If money is no object get the 2019. If you get the 2011 and the 2010 just don't demo a 2019. You will be completely happy with them but of course once you drink from the forbidden fountain...
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Fish tremble when they hear my name

A ship in harbor is safe -- but that is not what ships are built for.
--John A. Shedd, Salt from My Attic, 1928