The only probe I have something against is the conductivity one. They need to be calibrated every other month, and die after a couple of years. So that's easy: don't buy the PM2 module.
After that, the only other probe I changed was a pH one, replaced it with a dual junction from BRS.
I should be more detailed about the equipment I have:
- Apex classic: no problems, programming it is not bad at all (well I am also a software guy so that does help)
- 2 EB8 power bars: no issues
- pH probe: just replaced the standard one by a better BRS one after 2 years or so, since then no issues
- ORP probe: just working
- Temperature probes: no issues
- Leak detection: works really well
- Screen: the cord could be thicker, that thing is ridiculously thin and I can see the copper exposed.
- 1-10V control: easy to use when I needed it
- PAR meter: works well, but I chose to not let it inside the tank as it was getting covered in algae and coraline, which defeats the purpose of continuous monitoring
- PM2 (conductivity): don't buy that one, too shaky and useless
- DOS: a really good product, way more precise than my DIY doser with periscaltic pumps
- WXM control for
Ecotech products: works really nicely