I'm getting better pictures with the OM-D + Panny 100-300 the more I understand how I can customise the the OM-D buttons and settings.
The two dials to immediately change EV Comp and Selected Priority value (Aperture or Shutter etc.) are quickly accessible from shot to shot. Also, I assigned the Digital Zoom x 2 and MF enable functions to the readily accessible F1 and F2 buttons.
What all of this means is that after getting the bird in a frame, all of these settings can be quickly changed if needed with the eye still looking through the EVF.
Also as with most cameras, setting Drive to 4fps on pressing (or higher) will give greater chance of a good picture.
Still to research options for mapping ISO and Metering settings, maybe to the directional pad during record mode.
In manual mode, it seemed as if EV Comp was changing automatically, so hopefully this is an option to disable since prefer doing any such adjustments manually.
Typically I shoot in Aperture Priority and on occasion, Shutter Priority. Care must be taken not to crank the ISO too high otherwise blown highlights may happen (esp with Shutter Priority).
For focus setting, I find the AFS (Single Shot) + MF as the best option to get initial focus and then adjust MF if needed. However this is not easy with the layout of the Panny lens where the focus ring is a bit away from the hand and a bit stiff so I only use if the bird is pretty static. Very difficult to quickly MF with a target for less than a couple seconds. I also disabled the Oly magnify option in the EVF during MF as it always puts me off.
Currently I prefer the OIS in the Panny 100-300 lens (updated lens firmware 1.2) to the IBIS. I'm not seeing the great advantage of IBIS as yet as many of the reviews are indicating.
While the dials and buttons of the OM-D are in the right places for on the fly settings changes, the standard camera does not hold in the hand as easily as my Panasonic G1 body. In fact I would say the G1 is far superior in how it feels in the hand. Also, I'm a bit worried about the quality of the OM-D buttons. They feel a bit cheap compared to the G1 and not sure how long will last. A pity given all the great features of the OM-D.
Overall, the OM-D + Panny 100-300 is a very good kit for taking bird photos, once you are willing to invest the time to experiment with the many Oly settings. The horrendously expensive add-on Oly Grip would improve greatly the ergonomics of the setup but I'll pass for now since that cash can go towards another lens.
I would recommend. What I would really like to see is a 300mm F4 or a 400mm F5.6 quality lens.
Thats my quick assessment after using for a few days. Hope it helps anyone considering.