But last time the conversation was comparing a 10D with only 8 megapixels or w/e it has, which made sense. But cropping the inner APS-c FOV of a 6D wont giver you as big of a difference between the 60D right? As far as comparing a current APSC to a current full frame, that argument doesn't apply.
I mean if a crop and a FF shoot a 200mm shot, the crop would 'look' to have further reach, but that could be duplicated, could it not by 'cropping' the FF in post...and wouldn't you have a cleaner pic from doing that from the FF?
Answer to both of these is the same. From an IQ standpoint, there's not going to be a meaningful difference with contemporary sensors (for example, when I compared the 5DII cropped to the 7D, with no processing the 7D image was a little bit sharper and a little bit noisier...and some NR would reduce the noise and the sharpness as well). What you're giving up is megapixels...the cropped 5DII image is 8 MP, vs. 18 MP with the 7D. So the real question is, what image size do you
need, and that depends on what you'll do with the images. If you'll print 24x36" and hang on your wall, the 7D wins. If you'll print 8x12" for a coffee table book, there's no real difference...in which case, I'd pick the FF for the much better IQ when you don't need to crop, or can use a longer lens.
Keep in mind, also, that the above applies only when 'focal lentgh limited'. If you can use a longer lens, the FF wins, hands down. Back to the 7D vs. 5DII cropped comparison, I also compared the 7D + 85/1.2L II vs. the 5DII + 135/2L (basically the same framing and DoF at a given distance). The FF won, no contest...
Well, back to Rithmetic. If a FF camera has 16 MP then it's APS-C equivalent with the same size of pixels would be 16/1.6 = 10 MP.
You and Rithmetic.

You need to get better acquainted with each other. If a FF camera has 16 MP then it's APS-C equivalent with the same size of pixels would be 16/1.6
2 =
10 6.25 MP. Thus, a 6D's 20 MP image cropped to APS-C framing would yield a 7.8 MP image.