Prices are usually always cheaper. Lots of awesome things to see even if you don't buy anything! Also a plus that you wouldn't have to pay shipping to purchase the animals
Definitely go dude expos are so much fun and it's very difficult to not buy a new pet. There are great deals especially on food items (esp. feeder bugs). Depending on how long that particular reptile expo company has been operating there will likely be many distributors and breeders there (thus variety and options). If you're in the market or a new pet/ want to add to your breeding project, want some good deals, or even just want to see a whole bunch of beautiful reptiles in a huge room I say definitely go.