I think Sakura has more advantage compared to other characters because her animations are faster and moves are faster, so even when both players perform moves at the same time, most of the time Sakura's moves will hit. On top of that Sakura's combos are quite easy to link with each other, so therefore even small damages could compile to massive damage.
For all round offense and defense I would say Ken and Ryu, but I like Zangief aswell grab, crush, grab, awesome just watching it.
Casual users of Ryu and Ken are too predictable unless you are an expert using them. Gouken is probably the best one to use on SF4 because not only can he attack, he is good at counter too.
i hate the fact has a incredible recovery already a low punch shoryuken the fact is too many ryu players have a wierd similar play to Daigo Ken whereas he keeps the opponent up standing i say Ken is more fun to play with whereas Ryu is just to hammer your opponents and Ken got one amazing poking kick in real life it look so stupid but heck it can pressure people Ken in my opinion is more fun to play with Ken Ultra > Akuma Ultra is what i love