Hi FranC. The Buzz was my first (and only) step away from the 3.7 volt world, and I'm glad I took it. My decison was greatly swayed by the multiple safty features (I assume you've already read about them). As to performance, I did have some trouble at first with the little wire under the top cap breaking, but I sent it in and they replaced it with a longer, thicker wire and it's been chugging along quite well since. The batteries last a solid 8 hours, and the indicator light lets you know they're getting low long before performance is affected. Variable voltage is, IMO, the only way to go. As others have said, certain juices/attys perform much better at voltages that wouldn't be possible with a non-vv device (4.6, 5.3 etc). Long story short, it's a nice little device that I'd highly recommend. Fair warning though, you'll never look at your Ego the same way. Good luck with your decision.