If all you ever wished for was EA to continue making NHL games in the '94 format, then you won't be disappointed with these roms. There are no major visual differences between the original game and the roms except for updated teams, colors, and on-ice enhancements (coaches behind the bench, center ice logo, trapezoid net lines, etc.). Some people have mentioned that goal songs don't always match the teams from the original, but that doesn't bother me.
From a gameplay perspective, the AI seems to be better defensively, but I could be misremembering how the original cartridge played. The original game had a "weight/checking bug" where smaller players (Theoren Fleury) could truck everyone, but players with 100 check rating couldn't actually check. Some of the roms fixed that bug so that it plays more accurately. You can read about that bug on this site somewhere.
Other than that, the overall quality is outstanding. Naples39 and the rest of the people making the roms do a tremendous job and deserve a shrine in the Hall of Fame. Or at least eternal gratitude from this community.