What's the difference between Equifax, Experian, and Trans-Union?

I think they're all about the same.

These days not much - some companies report customer activity to just one or two agencies, some report to all, and again, when it comes to taking out more credit, some companies check all the agencies, some don't.

It's worth checking your credit record with all three (I'm not familiar with Trans-Union, but we have several agencies in the UK beyond Experian and Equifax), just to make sure there are no discrepancies.

It seems like you have to pay more to see your report from all 3.

I think the big difference between the big three is this Experian is viewed by most creditors as the most accurate bureau.

I honestly don't think there is much of a difference at all.  I get my free annual credit reports from all of them once a year and they report the same stuff.  I like TransUnion's reports the best though.  They have more color, are well organized and easier to read.  That's my only opinion on the subject.

When I worked in a back office at Citigroup processing loan applications, I never heard anyone mention that one agency was better than the other.  When a credit report was run, the system would run it through two of the three (didn't matter which one) and the most "robust" score of the two was the one that was used to make the credit decision.  They're all the same, in my humble opinion.  ...And even if one is more accurate than the other, the credit agencies aren't known exactly for being the most accurate of organization anyway.

Equifax seems fairly easy to dispute inaccuracies Trans unions call center seems to go to India. and Experian well better have a martini after talking to them, they are  downright grouchy.