Transferring from PC to imac..

Wee bit freaked out here..lol

My new first imac will be here real soon, and I'm a bit worried over transferring my stuff over to the iMac. I have read stories from super easy to **** online and in the forums. Best way seems to be using my network and the assistant that comes up right after first boot, or is it better to wait till it's up and then do the transfer, don't really want to do the external drive method. Have any kinks maybe been ironed out in mavericks in regards to this ??

Thanks guys....