I've just spent a whole day with the Pro1, and overall, I love the device. Here are some of my thoughts and issues.
It's a thicc boi! But I'm ok with that because it feels really solid in hand.
Keyboard opening clack is so satisfactory.
Holding Shift + alphabet keys on the physical kb doesn't capitalise. I have to toggle Caps Lock on/off for capitalisation which is slower and inconvenient.
Key modifiers really need to be sticky.
I'm using the Swype + Dragon virtual keyboard which doesn't seem to play nice with the physical keyboard open. If I tap to focus in a text input field with the physical kb open, it shows the virtual kb. Typing on the physical kb hides the virtual kb. Software issue that can be fixed, so it's a minor annoyance.
Software is rather unfinished in parts. Some settings areas with uneven spacing, some list items with no padding at all, update process doesn't prompt you to do anything when it reaches 100%, and some other stuff like that. Again, not a dealbreaker as these can be fixed over time.
The fingerprint scanner placement is the absolute worst for right handed usage. I thought the initial complaints were exaggerated, but nope! Most of the time, the palm of my right hand has reached the max failed attempts of unlocking by fingerprint before I'm even ready to do so.
There was some looseness at the top left area (bottom left in landscape mode with physical kb open) where the earpiece is. When it's loose, there is no audio from phone calls (except over bluetooth / headset / speakerphone). I fixed it by pressing on it to snap it into place, but it still gets loose if I open the physical keyboard too hard. My workaround right now is to use some finesse while opening the keyboard, but I would much rather prefer a permanent fix for this. This is probably the only disappointing thing for me as I expected better from a $650+ device.