I gave the Axis systems one heck of a workout later in the week at OSH, and also managed to corner a Garmin employee who'd put the install manual on his phone so he could answer the level of questions I was asking (for the most part anyway

). I played around mostly with the 11" + radio stack + 8" and the dual 11" setups for the most part, as those are the possibilities for me.
I've gotta say, I expect a lot from Garmin, but I think they have set themselves a new standard with these things. Super impressed. And most likely about to be super broke.
For those of you who don't like touchscreens, they did a really good job of allowing you to use the knobs for almost everything. The only thing I found that I wanted to use a knob for and couldn't was to zoom the traffic widget when the PFD was in full screen mode.
Just a few of the things that I learned:
* You can put in a second ADAHRS for a second display, but it must be a different model than the first so as to prevent any software/hardware bugs in the ADAHRS from taking down the whole system. The first ADAHRS is the GSU 25D at $4000, the second has to be the GSU75 at $10,500. You can also use a GI275 or G5 as a backup.
* You can get flap and trim indications on the PFD on certified aircraft now! It requires the GAD 27 Electrical Interface Adapter ($825).
* If you have GFC500 autopilot and a GI275 as your backup, you still cannot do autopilot failover if the Axis fails because the GI275 must be connected to the Axis via HSDB and *not* CAN bus, and GFC500 connects only via CAN bus so they won't talk.

If you have a G5 as your backup, it can fail over because the G5 doesn't do HSDB so is still connected to the CAN bus. I'm guessing that they made the decision to connect the GI275 via HSDB so that it can participate in Database Sync, but this is probably my biggest disappointment with the Axis since I already have the GI275.
* The data bars along the top of the displays are completely configurable. Remote mounted radios/txp/audio panel type controls must appear on at least one display if the Axis is what controls them, but with two displays you can pick and choose what goes where and you can have things on both displays if you'd like. Any space that isn't taken up by controls becomes data fields. There's a max of 8 data fields, but you can have a few controls up and still have 8 data fields.
* Same configurability extends to other areas - For example, if you have the EIS and multiple displays, you can choose which display gets the primary engine indications, including "both" if you'd like.
* Dedicated "EMER" button at the bottom, plus the ability for an on-screen EMER button... And what this does is really cool. It's not just Smart Glide, though it does incorporate that. When you hit EMER you get:
1) A pop-up window that offers you the option to activate Smart Glide, LVL, or a 180º turn.
2) A map that is automatically zoomed to encompass your best glide ring.
3) Buttons that can stick the nearest tower/CTAF in Com1, 121.5 in Com2, and 7700 in the transponder (if appropriately equipped - Otherwise it just shows the information so you can enter it manually if needed).
Smart Glide (which can also be activated immediately with an external button, or a long press on the EMER or -D> buttons) immediately puts a flight plan in to the nearest/best airport, activates the autopilot in IAS (set to Vg) and Nav modes (IAS and ROL if there's no airports within glide range), and bugs the altitude of the airport it's navigating to.
A final, undocumented feature I found: When you hit EMER, the flight plan to the best airport is created regardless of whether you activate Smart Glide. It doesn't flash the MSG button, but if you go into Messages -> New FPL you'll find it there.
Overall, it seems like they really thought through how to help you out as best they can given what is installed, without creating extra distraction. Well done.
* You can choose to have the skid/slip indicator be the little bar as it's been in most glass panels, or you can show a ball if you'd like.
* Available widgets currently: Map, Flight Plan, Weather, Traffic, Nearest, and G-Meter.

Above, you can see the best widget configuration on the PFD (mine, natch!): Nearest, Flight Plan, and Traffic. You can also see that there's still a lot of duplicated controls in the top data bar. Below, I've fixed up the data bar some, removing most of the controls from the second display so that there are lots more data fields available. That display shows the max number of data fields available (8) even with the nav radios and EMER button visible. Unfortunately I managed to get the scheduled message blocking the HSI data block on both! Also, note the flap and trim indications left of the HSI and below the airspeed indicator in both pics.

Of course, I've really loaded up the displays here - You can make this MUCH simpler if that's your thing. I've got the HSI Map active, three MFWs, AP/FD on, SVT, most of the display options except the flight path boxes (as much as I liked playing Pilotwings on the Nintendo when I was younger, that's a bit much even for me). I probably should have taken a pic with a simpler setup, but where's the fun in that?
Happy to try to answer questions if anybody's got 'em.