Interesting, but with Intuit Quicken and Microsoft Money available at very low cost these days, Mint will need competitive advantages other than price.
Mint is an online financial management service, clearly designed to compete with Intuit's Quicken and Quicken Online. Unlike many of the existing online banking and budgeting products, you won't run out of gas with this product too fast, although it does not have the depth of software like Quicken.
The product has an interesting business model: It's free. Mint makes money for itself, and for you, by looking at your spending habits and your accounts and recommending offers that will save you money. Got a high-interest credit card? Spending too much on DSL? Mint's advertising network will match offers from its partners to your particular situation. Mint's consumer pitch is that it will save you thousands of dollars a year if you listen to its paid advice.