I have had a Mint.com account since earlier this year.
The usage that most people use it for is to manage their budget, and set spending limits on certain things (such as clothes or other things that tend to get out of hand).
There are two features that I primarily use that I would recommend for everyone.
Net Income
I like to be able to look as the month progresses and see how my spending levels out with my income. Some months I come closer to the middle line (such as months when big bills, like auto insurance, is due) and some months I splurge too much (hello Xbox One) or am a great saver (I wish these would come more frequently….hello Amazon 
).
Credit Score
They give you a free credit score every few months, without having to file any paperwork or anything. Simply press a button, and together with Equifax (one of the Big 3 credit reporting company) provide the free service.
Mobile App
On a side, and final, note, their mobile app is pretty good as well, giving you a way to keep track of money flow wherever you are.
Aviously 