I'm using 14500 batteries. I have two PV's, one is a Mini Lambo/Hybris, the other is an EGo-RS. Both are variable voltage. I'm assuming the battery in the Ego RS is ICR. I've been charging them using the Ego charger. the battery in the hybris is probably IMR, it's 650mah and costs about 5 dollars to replace with the identical battery (it's L-Rider branded). I'm not doing anything extreme, usually vaping at 3.5 watts and 2.5 ohms.
The 14500 IMR's I've looked at all seem to be lower mah. On the other hand, reviews of ICR's I've looked at sometimes have commented that the batteries don't last as long as expected (when used in flashlights).
I got a Trustfire charger off a seller from eBay and two ultrafire batteries. The charger doesn't work at all, and the batteries it came with have worn tubing and I don't want to try using them at all. So, I'm looking for new batteries, but I don't want to spend too much money on a charger.