Ralph,
One newbie to another (looks like I joined a month or so before you). I had two pH kits before I got my TF-100, one came with the pool and one was in the house when I moved in, I think the PB left it here. One of them was an HDX but I threw them both out after a little closer examination. I did some testing and realized the Taylor is far superior, certainly for me and probably for most people. Here's how I came to that conclusion:
PH is very difficult for me in the first place as I've discovered I have a slight sex-linked color blindness in the color ranges for 7.5-8.0 on the Taylor color chart after an Expert on this site suggested the possibility. When I looked at the color comparator of the 3 units only the Taylor had colors that were discernibly different for me. I still had some trouble so I bought a portable digital PH test meter for about $20 and some pH 7 calibration solution (I'm a little obsessed with this chemistry stuff!). In my test comparisons of the 3 different test kits, the Taylor results were almost dead on with the calibrated meter and never off more than .1 PH unit. The others were way off (.4 or more) or were not discernible at all in the range. I've found I've been able to "train" myself with some good guidance from members here and the meter. Every time I check the meter now just verifies my Taylor drop test. I would have never guessed there was this much difference. The units all look about the same and I always thought they were indeed the same just packaged differently... turns out I was dead wrong on that!
So who'd of thunk it that I'd not only learn how to maintain and test my pool but I'd also learn about my own genetics? It's amazing what you can learn here!!
I hope this helps.
Chris