I think 5.45x39mm is pretty underrated as far as the greater gun world is concerned. The fact that we’re seeing more and more 5.45 rifles, both AK and non-AK pattern, probably means that’s changing, though arguably that’s largely the result of inexpensive ammunition.
Even this stuff, Hornady V-Max, which is “premium,” is damn cheap compared to its 5.56 equivalents.
The Mr. Guns ‘n’ Gear Channel has a lot more similar tests, which are quick and to-the-point. Lots of facts, not a lot of rambling. Worth checking out.