I think back to Phoenix, AZ in the 1990 when a good friend of mine bought a MiG-15 UTI from the People's Air Museum in Peking (or Beijing as the wind blows).
He was having dinner with some older former Chinese pilots and a discussion came up about Korea. He mentioned that the U.S. pilots noted the MiGs would sometimes go into a flat spin during hard maneuvering, and they all laughed and started speaking in Chinese. The translation was, "You Americans! You had g-suits and we didn't. Sometimes a pilot would pull hard and go into what is now know as GLOC. There is nothing wrong with the MiG if you stay awake and fly it!"
Two people can see the same event cand come to diametrically-opposed conclusions about the event.
To me, the ability to go past Mach 1 is nothing in the Sabre since that was NOT combat speed ... it was a steep dive. likely made specifically to go fast for some reason unrelated to combat. In combat, the F-86 and the MiG 15 were VERY well matched. I'd rather fly a MiG if I was going after bombers (due to the cannons) or flying from a rough field (due to the landing gear being trailing link type) but, otherwise, the F-86 was likely more comfortable and probably had better stall manners.
As it happens, the Planes of Fame flies both an F-86F and a MiG-15 bis. They are extremely well-matched in terms of performance, but the Sabre cockpit is better for U.S.-trained pilots since it matches our design philosophy.
An example would be the Sukhoi Su-27 series. In U.S. fighters the artificial horizon stays with the horizon and the little airplane in the instrument stays level with the wings of the aircraft. So, when you come out of cloud, the actual horizon is level with the artificial horizon and the little airplane is level with the wings.
In the Sukhoi, the little airplane stays level with the actual horizon and the artificial horizon goes to whatever angle is required to match the difference between the wings and the actual horizon. So, when you come out of a cloud, the real horizon is NEVER level with artificial horizon, unless you are wings-level, but the angle between them is correct.
If you fly the instruments in actual IMC, they act the same. If you mentally match the instrument with the outside, the Soviet (or Russian) system seems out-of-whack, but it isn't. It is just a different way of presenting the information. Neither is "better" if you are in IMC and cannot see outside references. But U.S.-trained pilots expect the instruments to match their visual cues when they CAN see outside. It's a matter of training only, but we (U.S. pilots) definitely prefer the way we have learned ... rather naturally.
I don't think the F-86 is necessarily "better," but it is better-matched to our way of doing things. The F-86 would have a very difficult time operating from a farmer's field, and might not even be able to do so at all. The MiG-15 is at home on rough fields. Maintenance on the MiG-15 is easier than maintenance on the F-86, by LONG SHOT. The Soviet birds I have had any experience with (MiG-15, MiG-17, Yak 50, Yk-52, Su-27, Su-29, TS-11, L-29, L-39) are all very GOOD airplanes. They have quirks and are all older airplanes, but a newer one, such as an L-159, is very high quality and operates as well as a newer U.S. airplane, assuming decent maintenance. Lack of same will tarnish ANY airplane's effectiveness.