No one seems to have hard numbers, but the general consensus is that the uptime is not up to industry standards. Otherwise DH would advertise a certain uptime and make stats readily availible.
And the quality issues seem to have been going on for the past 3 or so months with no response from DH.
This is actually surprising since DH relies on word-of-mouth advertising, and this isn't good for them.
One of my domains is relatively important to me, so I don't see myself signing up with DH again if these problems persist.