I dont have any mics (yet) but from what I have gathered; the only things that would make someone choose the AKG c1000's over the SP C4's is the fact that the AKGs can run off of 9volt battery as well as phantom power. *(edit) the c1000's has cardioid adaptable to hypercardioid caps , and the C4s can change caps from cardioid to omni directional.
I have noticed (just like Giz said) that the bass captured via the C4s is a lot more present than what I've heard off of the c1000's, the high ends-I haven't personally noticed either one shine brighter to me.
To answer your question, my opinion, based on listening to/comparing recordings, is yes they're good mics for the $.