Has anyone used priceline.com before to get reasonable rates on highly-rated hotels?

I'm going to be in Korea and Japan for most of August and I'm wondering if I should take a chance with priceline. The thing with priceline is that I won't know what hotels it would offer me until I submit my CC info (and it gets charged right away)

 

I've used it a couple times with good results. The most recent time I was about to book a 4 star hotel but decided to priceline it instead. I ended up getting the exact same hotel I was going to book for $80 less a night. score.

 

Since I'm not going to be there until August, should I do it now or do it few days before August rolls around?

 

not sure how effective priceline.com will be with an international booking. im sure it can be done but it may be cheaper to run with local agencies.