Hey, the Pintail is a VERY stable boat (pretty easy to roll too). It has been the reason why most of my customers have bought the boat.
Yes. They are two very different boats.
The Fun series is more like a playboat and the Pintails are faster and more river runner types that have some playboat characteristics along the lines of the Foreplay/Glide days, so you'll catch more waves on the fly and be more stable when on end.
You are actually a good candidate for the standard Pintail. The Pintail XL would be a good boat, but you are light enough that the regular Pintail will suit you well. I am 165lbs and paddled on all last spring and summer while I was recovering from shoulder surgery. It was a stable enough boat, and fast enough so it took good care of me in the high spring water, but it also was playful enough that I didn't feel the need to get into the park n play boat until I was fully healed. The Pintail is now one of my favorite boats that I have ever paddled. (here's a funny side note: every time I show up with the Pintail instead of my Fish, one friend kind of rolls his eyes because he knows that I\"m going to be a wave hog and be into doing multiple runs down the river so that I can make all sorts of speed based slalom type of moves, darting in and out of eddies, making s turns, etc)