If you mean "are Sakura's shadow powers awesome" then, yeah, I guess they are. But, if you mean "do I like the psychotic distortion of the sweetest girl in the game" then, no, not really. Dark Sakura is damn good at fighting, but she's not a particularly nice person, because of the corruption from Angra Mainyu (as the last bad end shows). Only Sakura's true nature stops her going totally over the edge, with the exception of that last ending, where Rin pushes her over it with her (apparent) complete lack of compassion for Sakura.
I like the idea of a Sakura who can fight like that, but has her usual kindness, though (but not necessarily her submissiveness, which comes from being abused by Zouken for so long). That would be awesome. Post-HF Sakura might well be like that, actually, at least to some extent.