I have a madvapes 5V 510 PT and it works well. You do need to make sure you have a USB source that can handle 2A though, and most computer USB ports can't. I got the 2A AC adapter from MV as well and it does the trick.
One thing to watch out for though - It occasionally goes into some sort of weird mode. A few times now it has stayed on after I released the button, and kept on until I unplugged it. After plugging back in, it would blink for a while (maybe 30 sec) before resetting and working as usual. I don't know if it's a "cleaning cycle" or what, but you want to keep an eye on it and pull the atty off or unplug it completely if it happens. At 5V, it will pop the atty pretty quick.