Teach Miami -- I am not a Yak expert. I looked at lots of yaks before buying mine. I previously have rented the OK Scrambler XT. I have never been in the Prowler 13. I can tell you compared to the XT the 15'7" Prowler is WAY faster and tracks WAY WAY straighter even with my crappy NOOB paddle stroke.
Mine has an optional rear hatch which is surprisingly handy. The 15' yak has a for sure disadvantage. It is GiaNormous. It only wieghs 6 more pounds than the 13' due to inch in width. It handles great in the water and I can turn it, manuever, start, stop all that just dandy. Getting on top of the truck and walk it to the water if there is a stiff breeze takes effort. I am not a small guy though (6'1" 200#) and it is not so much a difficult task but I can see if I where a bit shorter or a bit weaker I would have to rig something like rollers and use a cart instead of my method now of shouldered the yak and walking it across the parking lot, down the board walk and across the beach.
I like the all around life line it has. I started to add more clips until I took a good look at the lifeline. It is ran through mulitple clips. Anything clipped to the line would have to pull several clips out to be lost. I now just clip my paddle, gear or other stuff to the life line. I do intend to modify the front anchor point as of right now it is just the carry handle.
If you go to one of those video sights and type in "yak fishing" you will see tons of stuff. You might have to turn off the sound those fishing show guys sound like Fran Desser to me.