I read prologues when I must, but I try my damndest to avoid books with them. I only trust a few authors now with prologues. And really, their prologues are called prologues, but they're just first chapters. They start with stuff that's actually important and relevant to the immediate story, rather than a big info-dump of history or world-building.
It's my opinion, based on many a year of reading (especially in fantasy), that most prologues don't really need to be there. The author may think they need to impart all this information to make their story understandable, but usually they do not. Not if they're clever with their writing. Or maybe the information really is crucial to the story, but it can be given to the reader throughout the narrative instead of in one big, fat, usually boring as hell infodump.
To put this into perspective, I write historical fiction, and certainly understanding some of the history on which my fiction is based will make the reader's enjoyment of my fiction a lot easier. But as a reader, I wouldn't want to read a thinly-fictionalized history lesson before I got into a STORY -- which is, after all, what I paid for -- especially when a good writer can start with the STORY and give me the needed HISTORY unobtrusively and excitingly, as I read.