I like to put money I am going to spend in my Quicken register (similar to Money in my limited experience) and that is the big ticket feature missing from mint.com. Mint.com can only tell you what you did, or in a very general sense what you plan to do.
As a register, mint.com is flexible enough for me to categorize my transactions. As a planning / budgeting tool mint.com is very simple and fast to get going, but lacks the depth of a budget I want to manage every week. Mint.com also tracks my investments, but I freely admit my investment management is nothing more than putting money into the same accounts. I bother with investment tracking other than looking to see it isn't zero.
I say try mint.com. Mint.com has a place to totally delete your account.