MacBook Pro and BB9900

Dear all, can I ask a question, and if it's been covered elsewhere then apologies because I must have missed it. I have just bought a MacBook Pro with the latest software. I have been successfully synching my 9900 with my PC up to this point without any difficulty but I can't get it to synch with the MacBook successfully despite downloading the latest version of Desktop Manager for Mac. It sometimes just freezes/crashes although it has (rarely) synched (sunk?) but took much much longer than it would with the PC. I've given up and just gone back to synching with the PC (which seems an awful waste of my shiny new MacBook!). Is it ok to try to synch with both? I've seen elsewhere that there are issues with the MacBook being 64 bit (whatever that means) and so the Desktop Manager doesn't work properly on it. Is this true? I'm hoping that you, who are clearly much wiser than I am, can advise whether it's worth keeping on trying to synch with the mac or just stick with the PC?
Many thanks, Alan