I used to love it, but I think I still prefer Champion just because I don't like the speed. Strangely enough, Hyper Fighting is the only CPS-1 Street Fighter that I own. I think the main reason is that I played Street Fighter 3 for years and got used to the slower pace. I was actually kinda shocked when then didn't add a turbo mode over 3 iterations.
SF3 is already fast enough as it is (it's slower than Turbo though). Champion is slightly faster than The World Warrior.
Which has the best deeper gameplay and and the best graphics?
I think Super Street Fighter 2 is a lot simpler to just pick up and play but with worst graphics and sound....
Super Turbo is better than Super (better character balance without invincible dragon punches, and Guile doesn't dominate in Turbo like he does in Super).
As far as SSF2 vs Samurai Shodown 2, I would pick SSF2 as the best (but not the home ports of it).
The best 2D fighters would go roughly in this order:
Street Fighter III: Third Strike
Street Fighter III: Double Impact
Garou: Mark of the Wolves (maybe)
Street Fighter III: New Generation
Last Blade 1 & 2