so I have had 4 different kinds.
Battery tender, worked about 3 years and died. The warranty was worthless. They wanted me to pay for shipping both ways. it was about as much as the tender was new.
I have a ctek- but only because one car had an agm battery, otherwise I wouldn't have bothered.

I have 2 of the under 20 dollar shumaker's. I have had one of them for 2 years and the other under a year now. no issues on either.

I also had one of the cheap 4 dollar harbor freight one's. I used it about 6 months.
My only issue with it was that if you unplugged it, the car powered it up. so no reverse protection.