Until the K1 was released I had been shooting weddings/events with K3's and the 16-50 and 50-135 were my main lenses.
After making it through my first wedding with the K1 and 70-200 I was not sure if I wanted to deal with the extra weight.
I was not used to working with a lens that size and it felt unwieldy trying to balance it on my body with a second camera and lens (which I like to do sometimes.)
But then I pulled my shots into lightroom.
The sharpness wide open was like nothing I'd ever accomplished with the 50-135, the colors were so pleasing and required a lot less post processing (time saved) and the bokeh is beauitful.
I was never too happy with either the 16-50 or 50-135 wide open but I feel completely confident in the sharpness of the 70-200 wide open in any situation.
After that I decided it was definitely worth learning to work comfortably with the new lens.
It took me a while to adjust, you will find you support it differently than you would the 50-135.
I highly recommend attaching one end of your camera strap to the tripod foot and the other end to your camera as this is a much safer way to support the weight of the DFA lens (safer for the lens mount and easier on your shoulder/neck).
I use the peak design strap snaps which makes it really easy to change the anchor points of camera straps in a few seconds.
Zooming with it is a bit slower as I had to move heavier elements than I did with the 50-135 so I learned to anticipate my shots a bit better.
AF on the other hand is much faster and more confident than in the older DA* lens. I would say that the 70-200 is the most accurately focusing lens that I currently own.
In the AF aspect it has helped me capture fleeting moments that I would have missed with the old SDM motors.
All in all I learned to work with the weight and it has been well worth it.
The build and quick/accurate focusing of the 70-200 gives me peace of mind and the glass produces excellent sharpness, beautiful colors and creamy bokeh.
That being said I enjoy a fit and active lifestyle so weight may be less troubling to me than to some.
It is heavier which requires some adjustment coming from the 50-135, but learning to work with new gear is part of the fun and challenge that helps us improve.
The 50-135 was actually my favorite zoom lens until I learned to wield the DFA*.
Now the DFA* 70-200 2.8 is my new favorite zoom and my appreciation for it makes it feel much lighter