I use a Herpstat, a Johnsons, and just started using a Hydrofarm for my RTB. They are all okay, I am definitely more confident in the Herpstat, but the Johnsons and Hydrofarm do the job for now. Probably not the safest, but for the money they are okay. I've also heard Ranco is alright, comparable to Johnsons, and the new RBI VE-100 is getting rave reviews.