I use a hanna checker... I don't know if it's better or worse than any other but I do think it doesn't matter what you use as long as its consistent. Most testers should get you in the ballpark so as long as you use the same test each time to keep your parameter stable that is the important part.
I use the hanna checker. gotten pretty fast at it and very easy to use. I hate trying to guess on other tests with color. hanna gives you a number to read.