Perfect new tarmac, better than most roads back home. No services along the entire stretch though, so plan your fuel. It is a well traveled road, so if you have any trouble, someone will be available to help.
One to thing to consider though, depending on the weather of the day (very variable, passing rain showers to be expected throughout the year
) the police at the checkpoints on either end may require permits (issued by god knows whom?), police escort, or not give a damn. I have only taken this road once (quite recently) but then we had a military officer with us, so checkpoints were not an issue. From what I've heared, going from Kharga to Armant (Luxor) used to be easier than the other way.