I have used both the Canon 70-200mm F2.8L IS v1 and the Canon 70-200mm F4L IS on my 60D. These are both great lenses. They are sharp from center to corners on my 60D, and they both have color and contrast that I find very satisfying. I have not used the 70-200mm F2.8 IS v2, but I am sure that it is a great lens and likely better in terms of sharpness than the older lenses based on the reviews I've read. The questions are, what do plan to use the lens for, and how big to you plan to print your photos? The older lenses are plenty sharp for prints up to A3 (~12 X 17 inches, largest I've done). The F2.8 lenses will be better for sports and portraits, but the F4 lens is much smaller and lighter so it has a big advantage for travel, hiking, etc. Good luck.
I agree. I've owned the 70-200mm f/2.8 non IS, 4 of the 20-200mm f/2.8 IS, and two of the 70-200 f/2.8 MK II, as well as the 70-200mm f/4 IS. I've carried them on my 40D, 7D, 5D MK II, and 5D MK III.
I finally decided that the f/4 IS is the one to keep. The f/2.8 was not fast enough for my low light theatre shooting, and packing all that weight around for outdoor shooting was not necessary.
For low light, I've been using and expanding my collection of prime lenses, I can take shots that my f/2.8 zooms could not touch.
So it comes down, as usual to you! It does not matter what I like or someone else likes, since we all made a choice based on what we do. If you can, rent for a week and see what you think. You also have a 30 day return period to Adorama, and return shipping is less than rental cost in the event you do not like it.
The MK II is a wonderful lens, just not for everybody.