We cleared the entire place in close to 3.5 hours. The pace was pretty relaxing, with occasional 5 minute breaks and discussions of strategy and plans. I would consider our entire group experienced and very capable, but that's just an opinion, I'm sure there are top guilds who would consider us a bunch of casuals while others, very casual players, who would consider us really hardcore. So I'll go into a bit more details about us, to give others better idea what to expect based on your own group experience and abilities.
7/8 of us ran about 10 HM before and had about 1/2 Epic (purple from HM, dailies and Tionese vendor) and half leveling gear, we could generally clear an HM with 0 or 1 unlucky wipe. About 2 nights before, 4 of us ran The False Emperor for the first time and wiped twice, once on HK and another on the last boss, who I won't name to avoid spoilers. The 8th person was less experienced, with only 2-3 HM runs and mostly leveling gear. Still he was a capable DPS who could do his job well. I guess this can give a general idea on how capable my group was, so readers can compare their own experience and know better what to expect.