Currently reading Runaways and now at the end of Whedon's run (I think), I heard after that there was a huge downgrade on the story, should I continue reading it or switch to another teen team comic?
Depends on what got you into the book and what you're really looking for. The story wasn't as good after that, but they managed to remain faithful to the characters through and through. What got me on board was how distinct and recognizable each character's voice was written and their entertaining chemistry as a group. I could keep on reading as long as those needs were satisfied.