In your introductory session, they're going to work you really hard to make you feel extra out of shape. Then they're going to give you a hard sales pitch on buying some personal training sessions.
If you can afford them, a few might actually be worth it for you, especially if you have no idea what you're doing.
Yeah. If you're going in blind, some training will help you with form and get a general idea of how to use the equipment and some good routines to do. Just make sure you can get out of it without it being a huge hassle.