Let me be clearer. Apologies.
CTEK is what many major luxury car manufacturers use. Rolls-Royce, McLaren, etc. buy CTEK and rebrand it with their name, then up charge for it. To me, if it’s good enough for them, it’s good enough for me. For what it’s worth, I also bought CTEK comfortably based on lots of other positive feedback on the forum.
I have two CTEK tenders that I really like and with which I’ve never had any problem. YMMV.
That said, I’ve also had Deltran Battery Tender Jr. and never had any problem with that, though I have read about others who have.
I have no affiliation whatsoever with either manufacturer. I’m just sharing my experience. I would buy CTEK again but if I wanted to save some money and found a Battery Tender product that suited me, I’d try that too. I do really like the CTEK Powersport charger I highlighted above as it is made for motorcycles and will handle both lead-acid or lithium batteries. You tell the tender which battery you have and it applies different logic to accommodate. It seemed like a no-brainer as I currently have a stock battery but envision getting a lithium sometime.
Sorry for any confusion. I hope that helps!