Which one is better, and why?

I think SFA3 is better because of the option to customize the character.

And also blocking in air. Dammit I miss that in SFIV.

To be short....

Street Fighter IV. SFA3 was fun but I always felt that SFA2 was the best game in the SFA series. SFIV manages to have a decent size roster with good balance. Even Dan is usable in SFIV.

street fighter Ex 3 FTW!

That was really off-topic mister!

SFII Turbo is still the best for me.

Off-topic again...sigh.

I miss air blocking too, I also liked the 2 player vs computer from Alpha3. Hard to choose.

I havent played either of the SFs listed, so I added my own :]

Sorry Kos-Mos. So what did you like about Street Fighter Alpa 3 the most. I've played just about every version of Street Fighter there is. Maybe if we went into a more in depth discussion we could keep people on topic? I know that on Street Fighter IV, I've run into characters that either I can't use effectively or "low tier" on line and gotten owned by them. That is what I enjoy most about the game the balance. I had an awful day online yesterday. I couldn't Shin Shoryuken my way out of a paper bag, yet I beat all three Sagat players I ran into. And he is "broken" according to some of the whiners. Any character  can win. As much as I liked the wide variety of characters in SFA3. Roster size always seems to ruin balance.

Sagat isn't really broken or unbalanced. It's just that he's got the tools to be a good poker, mid range and long range fighter. It's also quite easy to combo into his ultra, resulting in huge damage with little effort or risk. He's probably the most versatile character with the lowest learning curve.

On Topic: I enjoyed alpha 3, but I'll give the nod to SF4, SF4 just seems easier to grasp. Also, I personally don't like custom combos.