I like the music in New Generation more than Second Impact. Good Fighter
New Generation also has some more details in backgrounds than 2i does, but 2i is obviously the much better game, gameplay-wise. Plus you get HUGO DA GAWD, Akuma, separated Yang, and Urine.
3s plays better but man did backgrounds take a hit. Music is totally different (I like it a lot still) and IIRC there's less detail on some sprites but it's been a while.
Also while waxing nostalgic on Street Fighter- I never saw 2nd Impact anywhere in arcades and to this day it remains the only SF game I never played in an arcade. The only time I ever played it is when I ended up with a Supergun, CPS3, and 2i at home for a brief period of time. Sold it off before W Impact came out on the Dreamcast that same year.