Nice review!
I had my misgivings about the Gemini as well but after using it for a while I have to say it works quite well and being able to charge two different packs at once is very convenient. I wrote a full review of this charger on my blog.

My charger is alsmot out of order after only 3 months use.
There is a short cut in one of the channel, so I can use only one.

ShortCut error with Eachine Gemini 2100 charger (1 min 10 sec)

Banggood does not want to take into warranty, so by this way they admit that the below average quality is normal.

Bad SAV on this one, I was happy from Banggood services, but when you have issue on product that cost more than 50$, then you discover the REAL aftersale service.

Originally Posted by MartMX

These chargers sure do have a different form factor, but still the basic 4 button interface. I would like to see a charger that requires the least amount of user interaction to charge a variety of batteries. Maybe slide switches to select LiPo, LiFe, NiMh and the cell count.

I want to be able to plug a battery in and balance charge it without pressing anything. My set of HobbyKing compact chargers will do that for LiPo, but not LiFe.

Have to agree there, my small cheapo chargers still my favorite to use. Just not good for bigger lipo's

Tech-tip #1 - 3Port balance charger (3 min 27 sec)