The Eagle has landed.
Picked mine up a couple hours ago. Haven't had a lot of time to play but here are some very early impressions.
1. IBIS is as advertised. Works great with my A-mount 135/1.8 on the LAEA. No visual confirmation of IBIS status like you had on A-mount which I miss, but it is doing its job.
2. Ergonomics - hmmm, I'm not as excited as some reviewers. I prefer the original A7's front and rear dials for aperture and shutter as they are much more rigid and provide better feedback. The new plastic dials are soft and quiet so will likely be a personal preference. I also don't care for how close the front dial is to the power switch. I have already turned the camera off inadvertently once. The shutter button placement, at first appears to be more ideal but I'm not so sure. It is positioned farther to the right of the camera body so you have to pull your finger away from the camera in order to fit the fingertip on the button. Maybe with a soft release I could get used to shooting using the crease of my finger which would be more comfortable. The button itself is less spongy than the A7's and requires less pressure to activate.
Haven't noticed any difference in the EVF although there may be some.
Keep in mind, I griped about some of the ergonomics of the original when it came out but today it feels like second nature to operate.
Beyond IBIS and ergonomics I haven't dug too deep yet but I did discover one KILLER feature that I am not aware was available on the A7 or A7s - Focus Hold. You can now program Focus Hold to any of the custom buttons, allowing you to hold initial focus between multiple shots. I can't tell you how many times I wished I had this feature outside of my lenses that have a hold button. BTW, C3 is about the only button you can comfortably program this feature to.
Edit* adding additional info from member questions directly to this initial post....
Steady Shot, when turned on, will activate when using focus zoom. You do NOT have to have the shutter half-pressed to activate.
In normal composition view (not zoomed in) you DO need to press the shutter to activate Steady Shot.
I think this is a very smart way to get the benefit of IBIS without a constant battery drain.
I confirmed this on the LAEA-4, the TechArt Contax G adapter, a VM M-mount adapter (no electronics) and a Fotodiox Contax G adapter (no electronics)
Auto ISO works the same as it always has on the A7 bodies. Sorry to burst any bubbles.