That just depends on what you value. The novelty factor of seeing four different ladies in one night? Or maybe having a threesome or a foursome or a fivesome? Or one lady to spend half the night with you? If there is a high-end provider who truly catches your fancy and has great reviews, I would be inclined to say, go with quality over quantity, particularly if you haven't tried that route before, and see if it's everything you've always wanted and more! But if there's no lady in that price range who is really drawing you, maybe better to spread it out in case one of the experiences is lackluster. I would probably avoid booking an extended session with someone you've never met before unless you've done an extensive amount of research.
Ultimately I think it depends on the ladies you're considering rather than the pricing situation. Having $800 to spend in one night greatly increases your options, though!
Also seems to depend on what you're into. Do you like intimacy, conversation, going out on the town, enjoying dinner together? Or are you in this to get off? Do you choose ladies based on who has the most supermodel-like body or are there particular skills you look for? It seems like a highly personal decision and I don't know how anyone could advise you about it without knowing what you are into specifically...