If you are a beginner vaper on the lookout for stealth, the iStick Pico Kit is a good contender for you. It comes in a small size and packs a decent punch; this kit is targeted specifically for newbies.
So Eleaf/Joyetech doesn’t really cater for the medium to advanced vapers, nothing new here. However, this is one of the few (if not the only one?) box mod that actually has a removable battery from them. Combined with a decent tank (Melo 3 Mini) and a reasonable form factor. I could see myself using this on errands or during the commute. As with all one-battery mods, don’t expect it to last too long before you have to recharge or pop another 18650 in there.
It’s actually a pretty smart mod, with upgradeable firmware and VW/Bypass/TC-Ni/TC-Ti/TC-SS/TCR Modes. The tank is a bit small at only 2ml, but it fits perfectly into the stealthy mod idea.
Later Edit: Just to clear something up, I am aware that there were some issues with the iStick 50 Watt devices made by Eleaf where people have reported them malfunctioning a lot or even exploding. This has gotten up to the point where I have stopped listing products from them on this site. It is safe to assume however, that due to the fact that you have a removable battery on this mod it is considered to be safer than the all-in-one mods.