I've been watching this thread with interest as I placed a pre-order for an Ergo Pro over a month ago from the 2nd production run (and I'm currently typing this response on a Mini Quiet Pro).
Based only on Internet photos and on PDF files showing the current layout of keys, I have the following feedback. I'm sure that if you ask 50 people for feedback on *anything*, you're likely to get 50 different answers. My intention is just to provide some ad-hoc feedback, and get a few questions answered.
By way of background, I'm a programmer, and my keyboard of choice for many, many years has been the Microsoft Bluetooth 5000/6000 series. The action is, well, underwhelming, but the form factor and the key placement are just about ideal on this keyboard. So I come to the table with an MSFT bias.
1. I really like the placement of *most* of the navigation keys on the Ergo Pro. But those 2 empty spaces on either side of the up arrow are begging to be filled with the Home and End keys, respectively. I'd like to see Home take up the left space, and End take up the right space. These seem like natural locations, too: Home moves to the beginning (or left) of the current line, End moves to the end (or right) of the current line. The pg up / pg down keys would maintain their current position. This cluster would keep all major navigation keys centered around the arrow keys and within easy reach.
2. By moving Home and End, you've now freed up space for re-introducing the Right+Ctrl key. Then you can ditch the non-standard placement for Right+Ctrl next to "N".
3. I'd like to see all 12 function keys in columns (not staggered) directly above the numeric key with the same number. F1 would be directly above 1, F2 would be directly above 2, and so on. This is how Microsoft does it with the Bluetooth 5000/6000, and it works great. The current staggering on the Ergo Pro seems slightly contrived by comparison. Even on the Mini Quiet Pro, I'm constantly missing the function key I want by pressing too far to the left or right. Touch typists have muscle memory to find numbers like 1, 2, 3, etc. Why not leverage this muscle memory by placing the corresponding key directly above its numeric namesake? Doing this would also help to balance out the 2 halves of the keyboard by moving F5 from the right to the left half.
4. If the function keys were in columns as spelled out above, this would provide more room for making the Delete key a little bigger (which I think it should be).
5. I understand the need to add Cut, Copy, Paste, Undo to the left half to balance out the two halves, but if this was the primary goal, I'd suggest the following: expose Cut, Copy, and Paste in a cluster and above that have another dedicated cluster for Undo and Redo. To me, a dedicated Undo without a corresponding Redo doesn't make much sense. You could use the space currently occupied by the overly large Escape key, and turn Esc back into a normal-sized key (or slightly elongated key) directly above the tilde.
Anway, I can't wait to take shipment from the 2nd production run, and I'm counting down the days!
