"how far are we from a fully working quantum computer?" A long ways.
Here is a Classical QuBit coins that are entangled, but not in any definite state, until an axis of observation is chosen, and the observation is made. The pair of coins is fundamentally different than the more familiar pair of gloves, that is usually discussed. A real glove, with the fingers curling towards the palm, is indeed in a known state before being observed - it is KNOWN, a priori, that a right-handed glove will be identifiable as such, REGARDLESS of what angle it is eventually viewed from. But the same is not KNOWN about a coin - it is not KNOWN, a priori, that a coin, viewed from every angle, will always be "heads".
Unlike "handedness", which is indeed an attribute of a glove, "heads or tails" is NOT an attribute of a coin. It is an attribute (like spin and polarization), of the relationship BETWEEN the observer and the observed.
Rob McEachern