Each one has its pluses and minuses. No one has it all. Yeah, read that again, let it sink in. You’ll go crazy trying to find The One™, so don’t bother.
Hence, I have an almighty Miboxer (hey, it says so right on the box), a regular mighty Opus, a Zanflare, and a Nitecore. All 4-bay chargers, not even counting the 1- and 2-bay LKs.
Most of the time I use my mighty Opus, but I have it on a cellphone/tablet stand oriented vertically to let hot air naturally waft its way up’n’out, as it gets heat-stroke pretty easily. And I don’t want the fan buzzing like an angry bumblebee all night long.
It seems to be the most flexible, so if you want to start with one, I’d go with the Opus (BC-3100 or whatever).
What Lightbringer said.
I’d add the Lii-500 and Zanflare C4, the C4 being my go to charger for most things, but the Opus has more features and power.
Internal resistance is useless on the Lii, and seems better than the Opus on the C4.
I’vce been using the Miboxer C8 for about a month now, so far so good. It’s idiotproof, its got only 2 buttons, it does everything for you out of the box, you can easilly configure current if you want, it seems to work like it should whetehr its 10180 or 26650 or Eneloop AA’s. I had tons of chargers over the years, this one seems fine.
Nothing under $50 is going to have adjustable termination voltage. A few chargers will do multiple chemistries so you can charge under and over 4.2v by setting that.
There is a hidden switch on the underside of the Opus you can access if you cut a hole in the case bottom. That will allow you to change that one.
Based on your recommendations, and further reviews of the chargers you’ve recommended, I’ve decided to go with the MiBOXER C4 or some variation thereof.
I needed a charger to do the longer 21700 cells and I went with the Miboxer C4-Upgrade. One amp for all 4 bays, or 1.5A for two bays is adequate for me. I’ve been happy with it. I like that it has the option for 12v with a standard 5.5 x 2.5mm jack or can plug in an AC cord. The Miboxer Upgrade C4-12 only has 12v input which is fine by me too. I use a 12v power supply that can source more current than most wall transformers. Nice to be able to use in the car.
For discharge capacity testing, I have a dedicated capacity tester (a ZHIYU) and didn’t need it built into the charger. (but seldom find a need to use it anyway). The new Miboxer Upgrade C4-12 (now has two yellow buttons) wasn’t available when I got my C4-Upgrade. Still waiting for it to become available on Amazon.