The first Gradius game I thoroughly played was Gradius III (SNES), 4 years ago. I decided to look into its arcade version, as well as its predecessors, and that's where I came across the AC version.
Then I tried the NES version and it just paled in comparison. You can only have 2 options (though understandable due to hardware limitations), you have a weaker laser, and I don't like the way the music was transplanted to this version. Also, stages 2 and 3 were taller, "wrap-around" stages (similar to a few stages in III) in the AC version; the NES version compresses them to 1 screen tall.
Other than that...maybe it's not so bad after all, after describing it. Maybe it's the hype that turns me away from more popular classic games?