At one point i really disliked her, but she has grown on me. After reading all the rumours about Karen leaving at end of Series 6, if there is to be any other companion i would rather it be River than someone new.

I liked her in season 4; not so much in season 5, and I think she is ok again in season 6(so far).
I don't know if Amy and Rory will be there in season 7(part of me hope they won't 'cause it would be exiting to see 11 find a new companion) but if they aren't, I don't want River to be a companion, they are suppose to meet in the wrong order not to travel together.
And half her charm is the mystery around her character. That would either disappear or become annoying if she become a full time companion.

SHE RULES in the episodes shes in if she were in any of the others like the rebel flesh for egsample she wouldnt be all that good and she wouldnt be a great constant companion but shes awsome in the storys shes in