I have used the water technique in the past. Also used the hold in the fingers, heat up the neck in the dark and dunk it in the water method. The problem with both is the uneven heating may heat part of the neck too much, or heat part of the neck too little to anneal it properly.
I had one case, a .22-250, where I must have gotten the shoulder too hot, because when I ran the case through the sizing die, upon extraction from the die, the expander ball pulled strongly on the neck so that the shoulder was pulled forward enough that the shell wouldn't chamber in my gun.
Generally, I didn't notice any other problems with using the "stand the case in the water" technique except sometimes it seemed that I had to apply a lot of heat to the neck to get all of it heated. I was concerned I was heating the brass too high and ruining it. Brass sitting in water acts as a pretty effective heat sink. That's why I stopped using it and went to the "hold the case between the fingers and heat in a dark room" method.
The temp sticks, with the case being rotated is probably the best way to do it properly for most shooters. However, it is slower than putting the cases in a pan of water first, then heating them.