Wow is my experience/opinion different from yours!
I find Quickbooks to be just horrible. I use the Windows version (under VMWare Fusion on my Mac) because the Mac version doesn't even pretend to support the only thing I still use it for (the credit card billing). But even the Windows version (which all of the following is about)...
Well, it is full of just plain bugs. For example, there is an obvious trivial bug in the forms entry for credit card expiration date for a customer's preferred payment method. The month always resets to 12 even if you set it to something else. I called their "customer support" about that one. After about half an hour on the phone with a clueless script-reading "customer support" rep, he obviously decided he had spent too much time and brushed me off (telling me to call the merchant services folk, whose problem it obviously wasn't). I wasn't expecting him to fix the problem, but I was hoping he'd at least pass it on as a bug report; no such luck.
I find the interface incredibly nonintuitive, complicated, awkward... just add every poor adjective you can think of for a poor user interface.
I rapidly gave up downloading my bank statements because it was so awkward to do and messed up so often. It was easier to manually reconcile.
It won't reconcile its own automatic entries. The month-end merchant fees get auto-entered as 2 separate transactions, but show up at the bank as a single combined one... and the reconciliation won't let you reconcile a single bank-downloaded entry to multiple transactions (like Quicken can).
And a host of other problems and awkward things that would make this post longer than the too long that it already is.
Eventually, I gave up on using Quickbooks for everything except the credit card billing (which actually does reasonably match my needs, in spite of the darned reset-month-to-12 bug). I moved everything else to Quicken Home&Business and I double enter credit card deposits in both Quickbooks and Quicken; the double entry is actually easier than fighting with Quickbook's management of my checking account.
Not that I'm thrilled with Quicken. I'm debating switching (possibly to MoneyDance) at the end of this year. But it is worlds better than Quickbooks. It seems obvious to me that Quickbooks and Quicken were done by entirely different groups, and it also seems obvious which group has a better handle on user interface.