I use Yodlee MoneyCenter to track my personal finances. Its UI isn't all that attractive, but it generally works pretty well. It automatically retrieves transactions from all my accounts, so I don't have to bother with data-entry. This is a huge plus for me; otherwise, I probably wouldn't do it at all.
But things fall apart when you want to follow a budget but you have shared expenses with someone. Say I've budgeted $200 for eating out. Yodlee can generate an "expense report" for that category, no problem. Except, what if I've only spent $100 on restaurants but my boyfriend has spent $400, half of which is my share? Then I'm clearly over budget, but Yodlee knows nothing about Forrest's accounts. Similarly, what if I've spent $300 on restaurants, but half of that is Forrest's share, so I've "really" only spent $150? Again, Yodlee has no way of dealing with this in its expense report or budgeting features.
On the other side of things, BillMonk is very useful for tracking who owes whom for shared expenses, but it has no personal finance reporting mechanisms at all (by design). So this doesn't really solve my problem either.
Enter Buxfer. As a former BillMonk employee, I feel like I'm "cheating" on BillMonk by even considering Buxfer. On the other hand, BillMonk never wanted to be a personal finance tracker, just a debt-between-friends tracker, so maybe I should let the guilt go. In any case, Buxfer does automatic transaction downloading and correctly understands how shared expenses affect budgets.
So I may be abandoning Yodlee and BillMonk in favor of Buxfer. Buxfer even has an API, so I should be able to whip up some script to take BillMonk's exported XML data and import it into Buxfer. (BillMonk almost released its API...) My group of friends still uses BillMonk, though, so I may have to write another script to keep my Buxfer account in sync with BillMonk.
I'll let you know how it goes.