No one charger is best for everything.
But the closest you can really get for "charge anything" that's high quality from a company that supports it (still makes firmware updates too), is probably teh Grin Tech Cycle Satiator http://ebikes.ca/satiator
There's more than one version depending on the pack voltages you're going to use it with; the higher the pack voltage, the lower current it can charge it at, due to the wattage limitations of the charger. But it works well, supports multiple chemistries, and you can set profiles for different batteries you use it with.