I used a 500R for about 3 years after I got my first bp. It worked fine and I didn't have a problem with it. Now, with that being said, it isn't digital, so it's harder to monitor and adjust temps. Any time I needed to adjust mine, I'd have to slowly turn it just a hair, wait an hour and check the temps again. Also, it seemed to allow a bigger temp fluctuation than the digital ones I use. It also needed to be adjusted more often than digital ones, although I'm not sure why. For about the same money, I'd go with the Hydrofarm for the digital display, but the accuracy and fluctuation are likely to be about the same. Make sure you're monitoring temps with a reliable and accurate thermometer, check and adjust frequently and you should be fine with either thermostat.