If you are partial to mac, as I am, then stay with mac. the PC will yield the same results, and for the same money you could get a faster computer. But an i7 mac is enough to do what you want. I use premiere pro/after effects and dont ever use FCP primarily due to the fact I have the adobe suite and it does absolutely everything. I also love being able to use dynamic link between AE and PP. Also, I have a mac pro so i am able to utilize the advantage in having a CUDA able card, which on the mac there are only 2 that will work, the gtx 285 which is discontinued and the quadro 4000(perhaps some other quadros work as well). If you are just doing basic editing then that will get you far. My issue is that I do post vfx and keying and the compression of a 4:2:0 camera using H.264 just doesnt cut it. I was seriously thinking of trading in my 7d for the Gh3 but as i dig deeper, even the high data rate of the GH3 doesnt come close to what the Black magic would. but I'm not sure how much horsepower that will take compared to what I have. To do any of this fluidly you need 16Gb ram minimum, 4 core minimum, and as high a processor speed possible. Some programs are designed to utilize multi core machines such as AE and Cinema4d, 3dMax, but typical applications still rely on single processors and will be fastest on a 3ghz core rather than 8 2.66Ghz cores. These files, even from a dslr can get highly render intensive. Even though compressed they actually can take more processing power to deal with the compression than you might think. always buy the most you can afford as technology changes so fast it's hard to keep up.
Hope that helps
Yuri
