I could see this being a big hit if they can get distribution for it as an alternative to business mobile phones. I've got a Galaxy S7 as a work phone but would much rather have something that's pocket sized with a real keyboard for editing docs, taking notes and emergency fixes when away from my laptop. Video conferencing too - very business friendly.
The £500 price ticket becomes less of an issue when your boss is paying. I can't see huge numbers of people buying one for themselves at that price, because you'd also need a phone. If your company buys you the Gemini and you run your own cheaper 'droid personal phone, you'd have a great little setup.