See I have been trialing OSX for a couple of weeks spending my time in the evenings using it instead of Windows to get used to the OS and I have to say it's very very nice.
I have experienced a few teething issues in Window management with regards to the dock. Although a setting exists in preferences that allows Windows to minimize to the icon (a la 7) instead of a mix of the applications side of the dock and the files/folders side on the right.
I found it really backward not having the 'snaps' functionality builtin. Third part software has cured this but seeing how I multimonitor between my laptop and my bigger screen not being able to pull Windows seamlessly between the two by default seems a little backward to me.
One thing I do like is the standardisation of applications. Where they adhere to Apple's strict human interface guidelines is more effective than in Windows I'd say.
It's convenient to always have Preferences in the same place across all applications.
The biggest issue I have is with Office for Mac, until Microsoft make a decent version of equal quality to the Windows counterpart then that is my only real issue.
Not having Foobar (without faffing with Wine) is one thing I found hard to stomach at first but seeing how I have an iPhone and an iPod I need to use iTunes anyway so I guess that consolidation of applications is best overall.
I do have one query, what is the equivalent of Services in Windows? I have seen Activity Monitor but I'm looking into disabling unecessary services such as Bonjour from running.