The Marriott Newport Beach is a very nice property and popular in the summer. Those prices are not bad considering you're looking for a July date.

Priceline is a gamble and you have to be willing to take whatever property they give you. I had an experience once where everyone posting online was getting the Marriott in Copenhagen. I bid figuring I had a decent chance of getting the Marriott, everyone else was. I ended up with a different property, good location but not nearly as nice as the Marriott.

Don't bid on priceline unless you are willing to stay at any hotel (4 star, 3 star or whatever) in the area you bid. If that doesn't work for you then you should book directly with Marriott.