Which is the best mobile carrier in terms of coverage and speed/reliability of data service?

So far I got a China Mobile / Peoples prepaid sim, and it works ok in my android phone for voice/text/data. But ... sometimes I see "no coverage" in various spots in HK, and sometimes the google maps is slow/patchy etc etc.

My real estate agent said definitely China Mobile is not the best carrier, he suggested SmarTone-Vodafone or PCCW. And since then I see advertising about 1010 claiming to be the "best" broadband mobile service - maybe they are, but I'd like independent info on that.

Ideally there would be a website comparing them, with coverage maps and network speeds. If I find such a thing I'll add it to this thread. I have been searching for it a little bit, which turned up threads here at geoexpat, but most of the threads are a few years old so out of date.

For great justice, please post if you have some good knowledge to answer this - thanks in advance.