Overall, the benefits have outweighed the differences and quirks. Though I've been a switcher since 2001, so I can't comment on this from a recent standpoint. Resizing windows hasn't been a pain due to having only one spot to do it from. Generally I set a window size, and rarely adjust it. Maximize used to bother me when I was still in the full Windows mentality. But now that I work in a more windowed mode, I rarely use it, preferring to just size to what I want. I've found the Windows mode of maximizing the app to full screen really breaks down if you go to a multi monitor setup, or to a larger monitor (with 30 inch being on the extreme here). I find myself manually sizing windows and never maximizing them on Windows at work where I have a multimonitor setup, just to ensure I can always drag a window to the other monitor without first having to unmaximize.

Keyboard support, I find myself using it more on a Mac then I did on Windows. Instead of hitting some key combination to activate GUI elements and navigating via the keyboard, I just hit the hotkey associated with the action. Most apps are standardized in OS X, so I have less menu digging to do. Find is a perfect example. Command-F works to activate find in every app I use on OS X. Window, not so much. Outlook was different then notepad, and notepad was different then textpad default.

OS X is different, but I wouldn't say it is broken, anymore then Windows would appear broken to a long time Mac user.