I bought 3 of these hoping to keep a fairly constant 21-24 degC as advertised. The ambient temperature in my brewing area is 19 degC so they didn't have much work to do. I set them up in the evening under new buckets of IPA and pinot grigio - by the morning the airlocks were bubbling almost constantly but the stick-on thermo strips indicated 26 degC! I switched them off and keeping my fingers crossed I haven't ruined the brews. They are very effective heaters but more suited to a colder environment (probably <17 degC) where they will bring the temperature up to a reasonable brewing range due to heat loss. I probably should have shelled out the extra £7 for the thermostatically controlled components rather than the fixed rate ones.
I've been using Festival kits for a few years now and they're very good. I've tried most kits and they're all excellent and easy to make. I used 'all grain' brew but I find Festival kits just as good and a lot easier.
I bought the Grainfather and chiller after going on a brewing course. Brew2Bottle offered the best price and the delivery was quick. Overall, price and service were excellent. I will be buying from B2B again.