I've never even handled or seen the push-pull version, but I have had the two ring and had to sell it last year. However *jumps up and down happily* I am about to buy my second and last two ringer! I loved the one I had and it killed having to part with it. Now I will say what gun owners say about having their guns taken away. "You can have my two ring when you can pry it from my cold, dead fingers!"
I am a pretty simple photographer, so I don't need all the latest whiz-bang features, which by the way would cost me 3 times what I am paying for my new lens. Just give me a well made, optically superior lens that will last me the rest of my days and I am happy.
The two ring is a delight to just hold and play with. It's that well made. Yeah, it's heavy, but with my Black Rapid Sport strap attached to the tripod foot, it rests pretty well on my hip. It's just one of those lenses that make you feel like a pro shooting with it. I am so looking forward to getting mine, which I am buying used from a fellow Nikonian, who is giving me a great deal.
I should have the lens by the end of next week, so a great beginning of the new year for me!