Which website would you recommend for reading authoritative reviews on mobile phones?
Personally, I like to see where they are manufactured (primarily). I'm trying to make a concious effort to not support poor labour conditions from countries that like to "under-bid" in order to get contracts. For my smart phone, I bought the LG P935 which is made in South Korea and as far as I know, their economy is similar to most 1st world economies.
After all that, when I was originally looking for a phone, I didn't find any review sites that I thought were of any use. People become biased to the products they have or to a certain point of view on a particular product. If you're going to buy, I would suggest going into your local provider that you think you may go with, see the products they are carrying and then go and individually research them on the Googles. That's exactly what I did.
My 6 pennies.
ALL "reviews" are tainted. Either the "review" is paid for by the manufacturer, a reseller, or a competitor, or at the very least the sample size is too small (user "ratings", typically only severely disgruntled and/or extremely happy people will bother).
Check spec sheets, look at the things for real, and make your decision.
cnet.com is a good go to place for phone reviews. But keep in mind, that should you be interested in one phone it does payoff to read reviews of other phones as well. You need to make your own judgement with the different options and weigh them against your true needs. For example, I have a Galaxy S4, with 16 MP camera. But the new Nokia Lumia 1020 is a true replacement with 41 MP. Because I have a professional photographer's background, the Nokia Lumia 1020 will be my ultimate phone of choice. I have had prior experience with the Nokia Lumia and as a developer and a business oriented person, the Lumia's rock by offering exactly what is needed at then time it's needed. But these are my own reasons. Review the options and find what is the most important features for you.