Sure, I mean there will always be two main groups of clients on the market. Those who trust in openness and those who don't care, or even distrust it. So there will always be a place for Yubikey.
But afaik there is nothing else out there right now like the tillitis key, programmable, 100% open, and already shipping.
If you have a key that can't be reflashed, source code is irrelevant. It may as well be hardwired circuits. Even Richard Stallman agrees on this point. I don't want a field programmable key, because it expands the attack surface.If you like weakened security, that's fine.
But afaik there is nothing else out there right now like the tillitis key, programmable, 100% open, and already shipping.