I did notice that the clouds do not scroll in Blanka's background in either version of Street Fighter II on the Sega Mega Drive. They also do not scroll in the SNES version of Super Street Fighter II, although the clouds do scroll in the SNES ports of Street Fighter II: The World Warrior and Street Fighter II: Turbo.
I enjoy SFII: Turbo and SFII:SCE equally; I do not prefer one over the other. I find that both ports have their advantages and disadvantages. The color palette in SFII: Turbo looks closer to the arcade version compared to SFII:SCE, although Sega did do a good job with the color palette on their system as well. The voices seem to be slightly sped-up in the SNES port for some reason, but it doesn't really bother me. I like the music in both ports equally; the Mega Drive version has music that sounds closer to the arcade version, while the soundtrack used for the SNES version is based on a SFII soundtrack CD (from what I've heard the CD was only released in Japan) that contains remixed versions of the arcade music tracks.