If you’re offered a job with more money/benefits or whatever, take it. Don’t give your employer the option to counter. And if you ever do let them counter out of curiosity, don’t take it… Leave.

There’s too many horror stories of people basically staying on after a counter-offer, only to train their replacement and end up tossed out anyways.

Loyalty doesn’t mean shit in tech; any promotion you get internally at a job will be pennies compared to what you’re able to get by shopping around; so do yourself a favor and run whenever the opportunity arises.