I mostly use the iPhone and iPad app, and Mint has been a great tool for me to see an overview of all of my accounts. It tells me how much I'm worth (!), allows me to create budgets, and shows all of my accounts. There are a few places where accuracy is lacking, like in the 'Cash Flow' section - ex: it shows my cash flow for the month of September as '$0 Earned', but I get paid on the first of the month. I find it does this every month so its difficult to see the exact overview of how much I make vs. how much I'm spending.
Accounts is a really helpful section, allowing me to connect all of my checking, savings, credit cards, and loan accounts to keep track of and make sure payments have posted. However it seems to have trouble with Sallie Mae loans, as it only shows balances and not account details for those.
Since the overviews are great but details can be fuzzy, it makes the Email Alerts (complete with a cute little pie chart of where your money goes) a little less helpful. I stand to be corrected on this since it may just be that I don't have a full, thorough knowledge of the app and the best way to utilize budgeting and reading account details, but overall I think Mint is something everyone needs to use.