Yes, they are very good and I have myself experience with a dead battery getting a new life - in my Yamaha snowmobile.
I have the charger connected to the Yamaha all year around - and when I start it in a new winter season,it starts at once!
Year after year........
Ctek has it´s main head office for construction in Vikmanshyttan, Dalarna in mid Sweden and in their Facebook site they "show up" a bit:
