If you we're disgruntled enough to look elsewhere in the first place. Getting paid more money won't magically fix all those issues. Never stay at a job after letting them know you had another offer. I did it once and ended up leaving 10 months even after a hefty raise.
There ain't no friends in the tech industry so who cares what happens to that chick unless she's family. Do you think she would turn down an opportunity for you if the roles we're reversed? With the skyhigh turnover rate in IT it's high unlikely you'll still be at either of these places in 10 years anyway. So only make moves to maximize your potential earnings. I could give a crap about any company or my coworkers. I'm all about this bread and would jump ship in a heartbeat if it means more money.