I've always enjoyed coming to trade shows and expos here. I like that it's TTC accessible, right by the highway, and lots of different rooms available. Lots of parking (yes there is indoor as well as outdoor). Traffic can bottleneck a bit getting out of the grounds, but that's expected if you're at a large show. Usually there are cabs out front when you want to get home. If you are going to an event here, consider other events going on at the same time (CNE, fireworks, TFC games) that can boost up parking prices or cause some traffic headaches.
Having worked on a huge event held here, I never had any issue with the staff or security (although I was not involved in the rental or contracts). I've also helped a friend out at her One of a Kind booth. I know some of the wireless credit card machines weren't working the night of my shift (no idea if this it was the venue or the carrier) so we just resorted to the old carbon copy paper method. Just in case, it would probably be a good idea to carry around some cash with you, especially if you're going to a show where you'll do a lot of shopping.
As others have mentioned, for food you are at the mercy of the event you're attending. They'll have the Pizza Pizza open if your show is big enough.