I would recommend it. It saves you driving around the country seeing all the different schools. Most distance learning schools bring their notes, so you can have a look through those. It also serves well as a shortlisting opportunity where you can work out which schools you will go and see in the flesh for either full-time courses or for the flying courses.
It does get very busy in-between seminars. If BA are speaking, everyone goes to listen to their pitch, so that's probably the best time to get the exhibition hall to yourself, and have some useful, quiet conversations. It's also at that time when you see just how many other people are thinking of training, and will be your competitor for those lucky jobs.
Parking is a complete farce, so its best to get there very early, or park in the terminals, and get the hotel hoppa bus.