I prefer online if it's a simple dispute that I think should be easily resolved. Example - my paid DoE collection still not being updated to paid on two bureaus after a month and a half.
However for more complicated issues like a returned DV where paperwork absolutely must be included for supporting evidence I prefer mail... I should figure out how to hook up/work this darned fax machine cuz it'd sure be cheaper....
Start 2/2008: TU 495 || EX 539 || EQ 528
Now 5/2013: TU 716 || EX ??? || EQ 702
Slate: $5000 Simplicity: $5000 David's Bridal: $3500 SW Chase: $3000 FNBO: $3000 Barclay NFL: $2500 BofA: $2400 Discover IT: $1700 Walmart: $1500 Victoria's Secret: $1000 Cap1: $750 Amex Zync: NPSL
(2 derogs to go until I'm squeaky clean in 2014!)