I've got 30L version. Using it for sparge and boil in 2 vessel system. Needs nice and thick insulation as @gilund mentioned. Replaced thermometer for therowell for PID. 30-40 brews in and no issues.
I don't waste any water on chilling. First hot water coming out of coil is used for cleaning. Rest is stored in 5L bottles, filtered and used in the next brew.