I have not used them on LHR / CMB but have done a few times on BKK / CMB in business. They are OK - good cabin crew and food and wine is to Emirates standard. In flight entertainment is similar to the old Emirates system. Seats are like Cathay regional services.

Locals translate UL as "usually late" but that has not been my experience and I have noticed that out of LHR their departure time keeping is usually good.