PS: All of it should be good for the K98 (Though I know my 2 crates of Ecuadorian have many duds) (Please note my incorrect spelling of Ecuador in my first response)
The TNW MG34 likes all of it (The Ecuadorian actually works better in the MG than my K98s), but I do find the 53/54 Yugo blows primers... It still works... but it isn't the best.
Romanian is supposed to be top notch, and you can almost never go wrong with Czech.
East German was decent, though I've heard guys complain of duds before.
Never fired my WW2 German stash, though if it isn't corroded from the inside out, apparently, it runs great in MGs.
Cheers!