I don't suppose anyone knows how this compares to the PS2 version? That one apparently has some annoyances, like a blur filter that can't be turned off, sound glitches in '98 ("READY...PERFECT!"), and an inability to play the arranged music during the game itself (the Japanese Orochi Collection with 95-97 let you do this!), but I remember hearing that the Wii version of SNK Arcade Classics Vol. 1 lacked the problems of the PS2 version. They were more severe in that case, like slow down in Shock Troopers, but I'm still curious.
Also, a ridiculously brief overview of how the games stack up (based on my prior experience with the originals):
94 - 95: Really show their age by now. Nice to have for the sake of completion and for some fooling around, though.
96: Fun, and about when KOF started picking up steam. The Boss Team in particular make this worth a look.
97: The engine really starts taking shape here, thanks in part to the introduction of Advance Mode.
98: Easily one of the best fighting games there is. Extremely solid engine, every character is worth playing to death, EX versions of certain characters...I play it regularly.
By the way, it's pretty awesome that the US version of the Orochi Collection got such dope original cover art.