Re point 2: As EliRivers has also stated, taking a counter offer when you have already stated your intent to leave can lead to a bad environment for both you an

Re point 2: As EliRivers has also stated, taking a counter offer when you have already stated your intent to leave can lead to a bad environment for both you and your employer. I don't see anything wrong with using that counter offer to try and negotiate a bit higher at the new job but personally I would suggest not taking counter offers.