A personal trainer for a short stint, just to get you started and to help you create a plan that works for you and is valuable would probably be a good use of money.
If you think that you are going to work out 4 hours a week for the next year. Thats a little over 200 hours of your time invested. It's probably worth talking to an expert to make sure you make the best use of that time.
Im not a fan of the long term trainers unless you are trying to get ready for some big event. They will obviously try to upsell you. Be clear that you just want a couple sessions to get started on the right foot and you should be okay.