I know its controversial, but the Mosin is better than the Mauser in many ways. It’s far more accurate in all except the Swede 6.5x55.
If you are mounting a scope, or building a hunting rifle, Mauser. If you are needing an iron sight battle rifle, a Mosin is fine. A Finnish rebuild beats any Mauser hands down. That’s based on a lot of shooting all of them on the surplus market.
And Lee Enfield’s are overlooked by everyone. But there’s a ton of truth in the saying that the Springfield is a target rifle, the Mauser is a hunting rifle, and the Lee Enfield is a battle rifle. And don’t forget, the Mosin wound up beating the Mauser side.
But right down to it, Swedish mauser, or Finnish Mosin M39.
Since we’re talking milsurps, my certain favorite is the Schmidt-Rubin K31. I know the Swedish Mausers in 6.5 are regarded as some of the finest shooters, but I don’t think they quite match a tuned K31. My K31 is a jewel that had no right being sold in its almost unissued condition. Sub-MOA shooter in anyone’s hands with genuine GP11. When I find a superior Swedish Mauser in the condition I want, I’ll buy it right there.
I have a Mosin-Nagant M91/30. It’s okay. I respect it more for its military history than anything having to do with it performing at a rifle range. I’d say that you can’t beat them for the price if it weren’t for a 1954 Tula SKS-45 I picked up as a curio for $75 plus tax 20-some years ago.
Also, as you mention, the SMLEs are wonderful rifles (depending on model, arsenal, and condition) but all the surplus .303 British is long gone.
I collect foreign milsurps and have a great many of them, some of my other favorites being French. No nation ever matched the French for furniture. For appalling strength, you’d have to see an Arisaka I own. I’ll get into USGI milsurps someday when I don’t worry about money so much.