I started going to Skyway about 15 years ago. I love the sweet butter that they use on the buns so much that I order my burger plain so that nothing takes away from that great taste. I have tried Swensons and have not been nearly as impressed. When we were in Wisconsin a few years ago, I was so excited to try butter burgers thinking they would be a better version of Skyway. I was so disappointed, they were good, but not Skyway good. It's on that bun!
I can't comment on other sandwiches because in the dozens of times I've been there, I've never been able to order anything other than a plain burger! My mom did try the baked ham sandwich this time around and really liked it, especially since the buns have the same secret sweetness.
I have started ordering the fries well done as I used to be very disappointed in them, they seemed limp and undercooked. Ever since I ask for them to be well done, they have been hot and crisp and yummy.
Go Skyway!