First of all you can get a computer with double the specifications for the price of a Macbook, so there is that. In terms of OS it's a matter of taste, but in terms of pure hardware a PC will always win in terms of price. That is assuming you pick out the components yourself and assemble the PC yourself (or have it assembled for you). Never buy a pre-assembled PC, especially for video editing.
As for Final Cut vs Premiere Pro, it's been a while since I used Final Cut but at the time both programs were pretty much identical. Sure some options are different and such, but both have professional video editing options and both are frequently used in the professional movie industry. So again it's a matter of personal taste. Both programs can load the same video formats and they can both export in the same video formats. Unless you have recording equipment that records in an Apple specific format there is no real difference to be seen.