Have been going to this show for a few years and actually prefer it over all the others held in Melbourne as there's just more stuff. Compared to Caulfield, like D4D said, there is a ton more room for different manufacturers to set up one or more models, plus a massive caravan section and a section for boats/fishing etc. There's also an inside sections with stalls.
We were looking for a camper trailer for ages so used to go there for that. We own one now but still like to go to get DIY ideas, plus check out the inside stalls and outside area where there's some shops set up. My brother is interested in caravans so we've convinced him this year to go with us.
Lastly, we bought a waeco and solar panel (with accessories) from there last year and reckon we saved around $700-$900 all up. You can definately get a bargain there but you have to know your prices to make sure you're getting a good price. Hubby really likes a certain brand of fishing rod but they were all overpriced compared to what you pay in the shops etc.
Hope that helps.
Cheers.