I used one for the past few months, totally worth it. Big gains both strength and size wise, Plus it really helped me to sort out some imbalances and problems I'd been having.

I'd say that if you do it's probably best to have a specific goal in mind so that the PT knows exactly what kind of direction you want to go in (I mainly went to build some strength up and sort the imbalances out, the size gains were just a bonus).

I'd say this though. If you're going to get a few sessions with a PT, don't half arse it and go with whatever BTEC sporting mouth breather happens to be working in your local fitness first. Do some research and find someone who really knows their shit. otherwise there's no real point. But if you do get someone with real deep knowledge of what they're doing it's totally worth it. They'll spot stuff you never noticed and give you insights you almost certainly wouldn't get on your own. It's changed the whole way I train tbh.