The thing with a cast iron pan and stainless steel pan is you've got to season them. Once they're seasoned, they have a non-stick (more or less) layer that's transformed olive oil, vegetable oil, or butter. I've been told that the jury's still out on which could be more harmful: that, or non-stick plastic. One advantage of a regular seasoned pan is you don't have to be afraid of overheating it past 350 or so degrees. Another one is you can use a metal spatula on it. With non-stick pans you have to use wood, or plastic (the latter option scares the hell out of me). As for the heat spreading evenly: it won't. Each individual pan and skillet has its own little faults and foibles.   I'm a great fan of Italian cuisine. I would love to cook French, but it's just too labor-intensive for me: I favor efficiency over meticulousness.   I use my pans to cook chicken, veal, lamb, turkey, fish, vegetables, and pasta, plus, occasionally, eggs and pancakes. All other things being equal, what's the best option for those who put taste first: cast iron, stainless steel, or anodized non-stick? Or should I try ceramic?  
I've never heard that boiling potatoes skin on makes a difference in consistency, but it's possible. The skin will act a as a barrier to moisture, letting the potatoes cook while absorbing less water. That will only work if you keep the potatoes whole though, cutting them up will negate that somewhat.   While skin in may make a difference the choice of potato makes a bigger difference. Waxy potatoes are not a good choice, neither are dry ones like russets. A medium starch potato is best, like a yukon gold or a maris piper.  Also very important is preparation after cooking. I find using a mixer tends to overwork the potatoes and make things gluey, while most chefs would recommend using a ricer. A ricer does give a great result but it is messy and lots of work. I use a potato masher and do it by hand, which to me is a good balance between speed and cleanup while giving a good result.  