That's a real shame you can't try one, I don't know why Canon don't push it more!!
Well I'm sure you'll love the 200-560 f4-5.6 (which is what it really is...!!) but I hope you aren't planning to carry it a long way!!
Don't know where you are geographically, I've lent mine to a few guys in Scotland and they've al bought them!!
I plan to carry it in my car for the long hauls and thereafter with a tripod (with gimbal) / monopod. That said, I think I need to hit the gym and work on my upper body, I might be able to use it handheld for more than a couple of minutes
I'm based in India and the DO lenses are seldom seen here (at least I haven't seen any).
1DX, 5D3, 600D, RX100
16-35L, 24-70L II, 70-200L II, 100-400L II, 50L, 85L II, 135L, 17TSE, 24TSE, 40, 100 macro, 18-55 II, 55-250 II, 1.4x III, 2x III, 600RT x 4
When it comes to gear, it is better to vote with your wallet. Bitching on online forums like a lunatic doesn't get you anywhere!