I've been using Thermapro and Accurite the entire time I've kept reptiles and have had no issues. Now as far as how accurate they are, I can't speak for that. I'm not in a lab testing them of course lol, but what I can tell you is I experienced the same issue as you, bringing home a "reptile brand" digital hydrometer and getting wildly different results. I even ran a test once where I got a 4 pack of some brand, I can't remember which, but sat them right next to each other in my kitchen overnight, and you should have seen how different they were the next morning.

Long story short, I don't think you went wrong with Accurite.