Which one is best? I just bought a Nitecore D4 and the metal slider inserts are as terrible and cheaply made as the 3 year old I2 I had back a while ago. XTAR I know is less rough of your battery wrappers upon insertion, while NiteCore chargers are too tight that damage to any battery I use it with becomes slightly beat up over a few cycles. I know about the dual bay 2A "SV2" or Rocket charger or whatever the name, but I would like an opinion on a good full feature, safe. 4-bay charger in the 20-25 dollar range. Any input would be appreciated.