I got my first "mass" deletions using Transunion Online disputes. One was Providian (thank God), another one was an smaller Student loan and the other was a collection agency account. I did have a couple of "updated" notations, one was from Discover Card , which i'm gonna continue to fight and the was Citibank Student Loan which has been a PIMA (pain in my azz) since day 1. Is Transunion easier to get deletions from?
I found TransUnion to be about the same as the others, except for the last negative (which I am still fighting them about). The easiest for me has been CSC (an equifax affliliate), my CR with them is clean sans one 60 day late. Experian has been ho-hum about everything, they are giving me trouble with the last negative as well. BTW, Discover is my last negative for both TU and EX. Got my first "Not enough info to dispute" letter over CHOD, even though they have disputed for less before. Anyhow, I prefer writing my disputes and sending them via USPS, as its way easier to prove later, if you have to. And besides the way they set up those online forms, with limited text input and few options, its like they want you to code the dispute for them so they can skip the imported data processor and go straight to pretending to investigate your dispute. Good luck!
I decided from here on end all of my disputes will be through Ceritifed letter. I actually did those prior to me knowing about Credit Net, but i knew that the best time to disputes things on your credit report is during the holidays.