I use E2's with an eGo. I've modded mine with ptb (see big
thread in tech forum). When they start to lose flavor and/or draw harder, I remove the ptb, rinse 'em in hot water, flick out the water in the
tank, dry burn until the coil glows brightly again with no residual smoke. Meanwhile I've rinsed the ptb and patted dry on a paper towel. I reinsert the ptb strips, fill and am ready to go.
Sounds like a lot of work but it really isn't. The final (?) revision is supposed to be shipping "any day now" and will hopefully resolve some of the problems with the earlier revisions.
Some folks may not want to mess with the current crop because of the little bit of work involved. For me it's worth it as they're the best performing carto's I've ever used when ptb modded. My opinion.
I've yet to lose any of the 7 I currently have in use and have lost track out of how many times I've refilled each one.