Klipsch Heritage stuff is the original high-end Hifi. Audiophiles were using Klipsch before stereo was even a thing. My grandfather bought a single Klipschorn in the early 50's to use with his McIntosh tube system and then later had to buy another for stereo when that happened. They are loud AF and will blow you away for Jazz and Rock. They can play more cleanly at high levels than any overpriced small audiophile minimonitors, including those that I own and love. If you like to listen loud, you will be super-happy with the Klipsch Cornwalls.
A lot of audiophiles have found the horns to be a little harsh and believe the phase coherency not as good for presenting a 3D soundstage. You can improve this by revising the crossovers and making felt diffraction pads for them.
Magnepan MG20.7s are some serious, Class A recommended stuff. When you are up to that level of performance, its just like buying "the best car in the world," whatever that means. I had a Rolls-Royce and a convertible Hummer a while back. Which was best? The Hummer was great for flying through the air and landing softly, driving over trees and running up and down the local river. The Rolls was quiet and comfortable. Neither were as reliable and easy to own as a Lexus. None of those can accelerate as fast as a Dodge Demon, and none of the above can corner like a Porsche... but my favorite car of all time is an old Land Rover.
The Magnepan MG20.7s can create a wall of sound that can hit you with slam and accuracy, delicate details, and if you take the time to treat your room for acoustics and fiddle with them enough, they can create a soundstage to wrap all the way around your head. Granted, Wilsons can image better than that, and the original Quad ESLs will make midrange and treble better than any speaker ever made... but the Quads can only handle around a 50 watt amp and are very inefficient and easy to fry, have no low-end bass, and a sweetspot smaller than the average human head.
So I recommend listening to a lot of stuff. None will be perfect. They are all a sort of compromise if we are honest. Anyone who says an MG20 is mid-fi is a baseless dick-measuring contestant.
I would put both the MG20.7s AND the new Cornwalls up there in the "best at _____" category, but they are great at two very different things. If you like them, buy them and just enjoy them and don't worry about online trolls with low self esteem bashing your taste.