To be honest I only bought the 75-300 (150-600 EFL) as it was £200 on the classifieds.
I don't really need that range I've only ever used it for compressing landscapes and in the studio (makes a surprisingly sharp portrait lens if you have the room)
Been looking at the A73 and A7R3 and really want one.
But I know it's just GAS and boredom and wanting to try something new and different.
During the past 5 years I've had a Nikon D7000, D700, Fuji X100, XT1, XT2, Nikon D750, Canon 6D and now the Olympus M5MK2.
All were great cameras (apart from the Fuji X-Trans bodies - Bloody worms and waxy skin).