One of the no-no's I do is mixing point of views. I'll have the main character speaking in the first while other viewpoints are presented at the end of the chapter. No one has really complained about this and I think as long as I keep those other POV as counterpoints to the main character it works for me.

That is until this latest tale of mine. My main character has been Shanghaied by a rogue AI Time-ship. I ended up with this back and forth thing going between the two with an occasional peek into the larger universe to remind my readers that lots more is actually going on.