I ran into this problem in the opposite direction. Taking a wallet.dat file from PC and trying to use in the mac client always caused the Mac client to crash. I looked into it a little and the Mac client build is one version behind PC and the dbversion value in the code changed. Unsure what other consequences there were of that, but I had to send my coins from my PC wallet to my Mac for them to work there.
I never tried the reverse (mac wallet to PC), but wouldn't be surprised if there's some gotchas on the way. Backup both wallets and send coins between them if you really need to have them on the 'other' computer.
I'm hoping when the promised updates arrive that a mac wallet will be compiled at the same time instead of being behind again :/
PC to Mac will always fail because the PC version uses Berkeley DB 6.something and the Mac version uses 4.8. The Mac version of Berkeley db is still on 4.8 so that it is 100% compatible with transferring to and from VPSes, many of which use older versions of linux that only have version 4.8 available in their package managers.
Moving from Mac to PC will work because it just upgrades the wallet.dat to the latest Berkeley DB version, but the other direction will not. The only way to get the PC wallet into the mac version or older Linux OSes is to dumpprivkey on the pc and then import it in the other wallet.
Hope this helps clarify things.