it's been a while since I commented on the thread.
So far I've used Price.com twice and haven't had any issues. For smallish purchases sub 5000HKD I have saved more than if i bought them on the high street here or the UK, it's been fun. I've explored some areas/malls that I probably wouldn't have known about in the process too.
Big Items i think you do pay more, especially in my case if your're looking for a specific model.
I've been on the look out for a particular hard drive which I've found 400HKD cheaper than the UK. I've also found a Sony projector which i was eyeing up for 2700HKD here and approx 4500 in the UK.
To conclude, some electronics can be cheaper.. just do your homework first!