Both of them were fun in their own right, although I actually enjoyed FF more however Streets of Rage was far more accessible at that time so I played it much more.
Final Fight 1 was funny because of the Cody infinity, and Street of Rage 2 was imo the greatest SoR game of all time, however Axel was broken in that game, and for only one move...Grand Upper, that was invincible did boat loads of damage and you even do the Grand Upper moving backwards.
Max was a powerhouse in that game as well and extremely stupid however he didn't have the dumb Grand Upper that Axel had.
Hahaha, I loved beat em ups theses were extremely fun, however other beat em ups imo were much better.