yoshiwo is probably the best guile in the world...
I think Dagger G plays a better Guile. Yoshiwo generally plays a turtle style Guile with good yomi in a sense that his jump-ins are usually spot on once or twice in a whole match and his reactions with heavy punches are excellent. He always turtles after doing a combo off a single jump in. In the video, he won the Sagat but I've seen him lose most of his matches against Sagat using the same tactic.
I think Dagger G on the other hand, has a more complete mastery of Guile as he can turtle and attack very well even if he is fighting Sagat. He's a lot more unpredictable and can zone better in mid and close range compared to Yoshiwo, who can only zone mid range. Also, he always uses the correct normal for the correct situation.