I started using mint.com as soon as they went beta a few months ago. I saw it as a tool to see and manage all my various credit card activity in one place. Also I want access to my information at any time and from any location, so I'm not a big fan of desktop apps like Quicken.
At one point I was using almost 8 different credit cards for various benefits and perks and watching my spending in mint made me realize that the hassle of managing all of them was not worth it anymore. Simplicity was most important to me getting ahead, so after tracking everything in mint for a few months I decided to stick exclusively with my Chase Freedom card.
I loved all the categorization, budgeting and visual graph features of the site and wished I could manage my checking the same way. I was weary of adding my bank info on the site but recently I thoroughly read through their message boards and faqs and decided to bite the bullet yesterday.
The reasons that made me go ahead are:
--mint runs on yodlee, a site that has been around for a long time and is quite secure
---Deleting your accounts deletes all information from mint and yodlee
--You're only liable for $50 of unauthorized transfers from a bank account if it's reported within 2 days.
--they are Verisign certified and 128 encrypted
--I only keep 2 months worth of bills in my checking account, so my liability is low, although I don't ever foresee adding my investment accounts to it.
Now all my checking account activity, along with my credit card, is nicely categorized with notes and I have a good visual indication of my financial standing.