Ok, there is very little info about the 520 in english. Seems to have hit europe, but not UK. Here is what I have found:
It is
slightly thinner than a regular 510. It's batt is 2 or 3 mm longer than a 510 batt, but its thinner. Two things I found that are important are: it vapes a bit cooler than a regular 510, and the battery lasts about twice as long as a regular 510. Both of these things could be explained if they are using an SBL 510 atty, which is a bit higher resistance than a Joye 510 atty, and would explain the width (reported with those buying it for a 510 and not having carts fit), the batt life, and the cooler
vape.
I found no one that spoke english posting on it. All
reviews are French or some other euro language.
The idea was to make a 510 that had better flavor, which high-heat tends to kill. My guess is there is less vapor, but
juice will last longer. Seems the 520 atty/cart is compatible with regular 510 batt threads. The attys are the same price as regular 510 attys.
Wordup has them:
Starter Kits
I recommend getting an atty to try on a 510 batt, if you don't want to shell out for a whole starter kit. It will work on the regular 510 or mega batt, and will tell you whether the vape works for you. I predict less vapor, more flavor, less juice consumed.
I found no one here on ECF that uses one and has posted comments. I does sound like a nice atty though, and if it is like an SBL 510 atty, should be very good on true 3.7V PVs, like a 14500 mod. As for atty life, I do not know really, but it sounds like as long as it doesn't clog a lot, it could last longer than a hotter 510 atty.