DMS,
I tried a couple of cheap ones, and to be even close to accurate you need to calibrate them almost every time you use them. It was more of a PIA than I wanted to deal with.
The pH test is the primary reason that I bought the LaMotte ColorQ. It gets a lot of bad press here, but it works well for me for everyday tests. I also have the TF100 that I use when accuracy is an issue or I want to measure FC above 10 ppm.
Thanks,
Jim R.