An unplayable, laggy, buggy mess. My fiends only log on when we want a laugh at how pathetic it is. It's the first game I can confidently describe as impressively bad.
Last update had 10+ minor cosmetic tweaks and ZERO bug fixes. This is the first piece of software I have ever seen an update be pushed with not even a single bug squashed. They spend more time on chicken footprints then on bus.
Of course there are bugs galore, pick a random line of code in any source file and I bet you it needs be rewritten. I suspect Blizzard doesn't want to pay for qualified talent - so they don't.