Jeff I do have a yak question for you on your new latta holder it looks longer of more narrow all most like a touring yak does it go thru the water easier than other sit ons you have tried?
The Search 15 (latte-1? latte-express-O?) is longer and narrower and definitely has a sharper, deeper shape cutting the water than my Redfish 14, so it pushes less water. I notice the difference mostly as I accelerate from a stop toward cruising speed - where its much more responsive and noticeably quieter. It also has a longer glide than the Redfish. I think my substantial weight muffles a lot of the benefit it would show for an "average" sized person... That's where the buoyancy and stability of the Redfish pays off - its jut not tippy at all. I don't notice any difference in cruising speed - there probably is some on the GPS, but you'd have to do a lot of testing to prove it and factor out coffee, sleep, breakfast, wind, current, etc... The seats are sort of a wash - the bolt-on Redfish seat is a little flat but more comfortable over the long haul where the molded-in Search is more pleasant initially but wears on the tailbone after a while.
The Search doesn't turn quite as well due to the stronger keel effect (but its not like the redfish swings about on a dime itself, so this isn't saying too much). The other thing I notice is that the undercut on the bow catches and echos hull slap much more than the Redfish's vertical sides.
Pluses and minuses all around. I've got the rudder, the fish finder and the anchor trolley on the Redfish, so it wins on the basis of rigging and extras sometimes. The Search is a little lighter and a little more fun to paddle - you feel more like part of the boat and more like you're in a kayak - so it wins sometimes. I expect the Search will do really well if & when I paddle the surf. That big nose ought to slice the waves where the Redfish looks like it'll take more of a beating.
Overall there's not a huge difference for me so far. Nice to have a little variety and nice to have a spare for bringing somebody along.