This morning I called TU to dispute a few items on mine and my wife's CR's. In general I feel TU is probably one of the easiest to dispute with. Here is my list of TU's pros and cons:
PROS:
1) Easy to navigate phone system (only 1-2 steps to get an agent).
2) Quick response - got an agent within 3 minutes or less each time.
3) The agents are generally pretty friendly.
CONS:
1) Agents sometimes speak to quickly or not understandable (call center is in India...).
2) The agents are quick to "pigeon-hole" your dispute into a certain (sometimes innaccurate) category; when another category would be more suitable.
So far, my experience with them has been favorable with the exception of one item which they investigated under an inaccurate category and I had to dispute it again.
Their website dispute process, by the way, is also not bad.
FICOnater2007