I've never been to this one and the cost doesn't appear to be too outrageous when compared to other similar conferences, but... Only you can provide a meaningful rating. What would it mean for you/your startup? You should never assume that just by showing up you will walk away with cash in hand. In cases where you have a chance to present, it's safe to assume that you're either the customer (because you paid) or the bait (if you get to attend for free).
My advice with any of these is to have specific goals and targets in mind and that you actively work towards them. Ex. greet 100 attendees and unboard 10 new customers, or meet 20 principles and setup follow-up meetings with 2, or connect with VC X in particular and start cultivating a relationship for a later funding round. If your goal is just to learn, consider the cost in terms of money, time and loss of progress on your current project.
Finally, once you've exhausted/maximized your opportunities, just go ahead and leave. Sometimes you could hang around to connect with that one target when the dust clears, but be aware that by then, they might just want to go home. If you've hit it off or they know you from a previous encounter, you may get a chance to hang out (esp if one of you is in from out of town). If you get that far, great - now work on building the relationship by getting to know them better, but keep your wits about you so you don't end up in a terrible situation...