We use Vernier Labquests in our building. The flexibility that they offered sold us. That being said...They were more expensive as compared to some of the others, so we had to buy fewer units. Had them for 3 years and have used motion, ph, and temperature sensors with my 5-8 graders. I'm glad that we bought them. As far as the competitors, I cant offer a practical comparison. Hopefully others will chime in....