I've never been one for personal trainers, as I have seen numerous "personal trainers" have people bend over frontwards with a Smith bar on their back and call that a "squat". On the other hand, I knew a guy at my old gym who was a retired NFL player who was one of the best PT's you'll ever see, but then again, when he was training for football, he had top of the line PT's training him. Cheap, cookie-cutter gyms that you can pay $9.99 a month for are going to employ "personal trainers" who make $10 an hour who had somebody "teach" them how to train people for 2 days before they cut them loose, unlike Goldfish who if he told me he was going to get my grandmother doing dead lifts, I would trust him.
You get what you pay for.