No matter where we go we do blend both guided tours in and also just roaming around on our own.
We only have two full days in HK and I think taking up 1.5 days will allow us to see a lot and then still have evenings and part of the other day to bum around and shop and other things.
If we had longer time there I would still end up throwing in a tour and then using our Eyewitness guides for the rest and also the conceirges input.

Overall I know they can typically be overpriced and a rush through places, but sometimes that is enough to get a flavor for what is there and then the next time if/when we come back we have a better idea on what me may want to spend more time and focus on.

Either way we are excited to visit and hope to see many sites on our short stay.