Picked up a Vision Nano yesterday, for my Joyetech 510T. At first there was a bad plastic taste, but that's gone now. I've gone through nearly a whole tankful of FlavourArt 50PG/40VG.
The problem is, compared to the stock 510T, it gives noticeably less vapour, and is quite harsh - enough to make me cough. It's not exactly a burnt taste, but maybe getting close. I let it soak overnight, but no change. Disappointing, because I'd read a lot of good comments about it.
Hard to say, but it seems like maybe it's just not getting enough liquid throughput to the coil? It's 1.8 ohms (I tested it), so I guess it also burns a bit hotter than the stock one. The stock one sort of crackles a bit while drawing, but this one gives more like one or two louder pop sounds near the end.
Did I maybe just get a bad one? Not sure what to expect. Shouldn't it be an improvement over the stock 510T? People talked about "lots of vapour", etc... I guess it's cheap enough I could try another one, but hate to throw good money after bad...