If you are worried get this:
Nitecore Intellicharge F1 Smart Battery Charger for Li-ion, IMR Batteries
Sorry about the blue text as pasted the name. I have one and the pro being you control the battery which IMHO is the potential issue with any of them. You know the history of the 18650 being used and if there are problems like the battery was overly discharged (the F1 has protection against that) or somehow exposed to whatever just replace the battery.