Migration Assistant - basic quaestion

So...I have an iMac which works fine and I use (and will continue to use) it for everything. Just getting a new MacBook Pro, and I know that it will ask if i want to migrate all my stuff over from the iMac.

Is this process completely non destructive? That is to say, can I end up with exactly the same programs and data on both PCs? I always thought that there was no such thing as a free lunch, and that maybe there would be licensing issues with software or something??

On a related note, is there a simple way that I can then keep data (e.g. photos. music etc) synchronised between the two computers so if I work on a photo in Aperture, say, that it can update the Aperture library on the iMac.

Basic newbie questions I'm afraid!