It all seems to depend.
EQ has proven very difficult to get an incorrect variant of my name removed. Addresses were not a problem to get fixed, but the name thing is making me inclining to send an ITS (Intent To Sue) letter.
EX has the names and variants all correct, and they removed the incorrect one (which I think EQ originated) without problems. Addresses however are proving impossible. Sent them a list of all previous addresses, validated thru the USPS website, and they ignored it. Got a few deleted via their website, but they recently added a couple of new and incorrect variants. Thinking ITS with them as well.
TU was very easy to get addresses corrected, and they didn't have any bad name variants. They did however recently screw up the wife's report and updated our current address by dropping a couple of digits outta the address. Some people's children.