Nothing is meant to be easy and the A7R is going to work but seems to need some thoughtful use.
The "difficult" EF 135mm f2.0 now seems to be working at quite acceptable auto focus speeds but takes some fits of its former self from time to time.
The accuracy seems to vary. At flexible spot (small) it is quick but not so accurate, but it might be better in some situations than others - I can also try medium and large - so many lenses/combinations .... The "center" focus point is more accurate at close defined objects but on the fuzzy side for two handy but reasonably distant wallabies.
I think that when I work the changes and get some normal type activity I will be better informed.
In the meantime it is the Olympus E-M1 that has become the star turn - it is Purrfect with the once cranky Canon EF 135mm f2.0L lens. Spot on quick AF that does not have to be "managed" like that of the A7R. Right at the moment in the midst of my experimenting phase the images form the lowly 4/3 sensor would blow those from the FF sensor A7R away. (Sorry guys but I hope I can do better if I work harder at it

).
The same lens tried on the Panasonic GX7 continues its multiple re-tries habit, but when it does lock properly it is tack sharp. This lens is now a standout on the E-M1 body.
The Canon EF 70-200 f2.8L OIS.
Sony A7R Metabones IV v0.50 firmware - acceptable AF speed and accuracy - I would not call it as tack sharp accurate as might be expected of a camera with a FF sensor, but there is tweaking time available. But the fact that tweaking time might be necessary is the worry.
Panasonic GX7 Metabones Smart Adapter v2.3 firmware. Needs retries mostly but then is tack sharp. Worthy for use, but that once only chance for a prize winning shot of a moving subject might be lost.
Olympus E-M1 Metabones Ultra FR Adapter v2.3 firmware - fast accurate (oem level?) AF tack sharp. The easy winner.
Just for completeness the Sigma 4.5mm f2.8 circular fish-eye works fine on the A7R but the vignette is huge with the image a little circle in the middle of a vast sea of black - it is designed for the aps-c image circle and actually seems to perform at its best with a Smart Adapter in 1:1 crop on a M4/3 camera. Just the right amount of 100% frame on a circle image. Better looking than its native aps-c in fact.
I must away and do something useful with my life but I expect the Metabones new firmware and its performance on various lenses is going to be the usual story of variations of success. For the moment the v2.3 firmware has made the E-M1 the standout performer and maybe v0.51 firmware might iron out the precision of the AF accuracy on the A7R at least - my observation seems to be that it is just a litle on the fuzzy side of perfect. Funnily enough even MF does not seem to improve it - it might be a factor of the default extreme magnification of playback - in which case it is my mea culpa.
Don't know really but the E-M1 has improved very obviously and if anything the GX7 is not quite as good as it was with the earlier firmware.
Images captured are too experimental as of yet to be worth showing - and of course I have already forgotten which lens took which shot apart form the very obvious ones - maybe the EXIF would help ....
I have not tried "green" mode.