QuickBooks is not a bad solution, but it is typically used by smaller companies since it is not a true, auditable accounting system. Dynamics is much more robust than QuickBooks and handles complex accounting much better.
FinancialForce may be a good option if you are looking for something that is on the Force.com platform. If you are already a Salesforce.com user and are looking for an accounting system, this may be the way to go. However, if you already have a good accounting system, I would not suggest making the switch to FinancialForce. My experience with it so far has been that it was designed by engineers as a solution for people using Salesforce, not as an accounting system. There are many red flags right out of the box, and customization seems to be far more difficult than initial expectations. For example, the system does not use debits and credits, but rather positives and negatives. This is mind blowing for an accountant! Out of the box, there are three screens to click through just to create a journal entry. Reporting falls anywhere from difficult to impossible. My CFO recently spent the better part of a week trying to run a YTD Trial Balance. Again, mind blowing that this is being called an accounting system.
Dynamics definitely feels like a much truer accounting system than either of the other products that I've worked with.