Can't comment on what they taste like now, but back in the mid '80s I thought both were pretty decent. I was sternly instructed by philadelphian friends to order "Wiz wit", then shut my mouth and step aside.
This thread made me do a little Wiki-digging on the subject. I dont remember everything I read, but part of the story I recall is the sub started with a couple of hot dog vendors who started making chopped steak sandwiches for themselves and started putting onions with the steak then on a roll. A cabbie saw them eating them and asked for one, the word got out and they switched to selling steak subs and it took off.
Somewhere down the road, other people started making the subs and began adding cheese. This was long before Kraft invented shelf stable cheese with sodium citrate emulsifier (what I use for mac and cheese today...not Cheese Whiz, my own molecular Keto cheese sauce) and eventually what we know today as Cheese Whiz.
I always thought the "Wit" was about the Cheese Whiz because all I ever saw was on TV food shows who featured the most well known joints, the now iconic ones. But, from what I read, long before the advent of "Whiz", the question or statement of "Wit" was whether to add onions, not cheese.
But, in the modern day, this (Wit=Whiz) is the lore, likely invented by one of the now big players in the "Philly CheeseSteak" scene but is really just how they talk in the city. So, what makes a CheeseSteak has been highly polarized by these modern day "requirements". People can argue all they want, but the original didn't even have cheese and chances are you can get a better "steak sub" at the many other restaurants all over the country where they arent rushing the assembly and essentially insulting a customer who simply needs a few seconds to make a decision! To me, rudeness makes food taste worse
I aint standing in line for that!