HEL is my favourite HKG-Europe transfer, if I'm not flying direct. To add to your points, transit in HEL is very straightforward and efficient.
The biggest issue (for HKG) is the too-high probability of the flight being delayed overnight. The length and timing of the sectors seems to means that they are the first to be disrupted in the event of any technical issues. Some discussion here -
Delay problems of AY69 / AY99 HEL-HKG
Most recently it looks like there was a 7 hour delay on 28 Feb.