There really isn't and I challenge you to find a year they had releases at the same time and SNK had the better game. It doesn't exist. Even now; KOFXII was maybe the most dissapointing game I've ever played and I REALLY WANTED that to be a tier zero game but it was slow and awful.
At no point was it better. Capcom vs. SNK 2

compared to SNK vs. Capcom
If there was any point in time, it would be King of Fighters 2
That game was ported to SNES/Genesis so those who couldn't afford Neo-Geo finally got to try a game out
And it was fun, the graphics was excellent at the time
But here's the thing, Capcom themselves haven't topped Street Fighter let alone another company
IMO, SSF2HDR >>> Any other fighter.
MKII was my 2nd. And this newest MK that dropped last year is a BEAST.
But fighting games need something new. Its too much of the same old shyt
Like, we need a new IP that doesn't heavily borrow from a pre existing game