In about a month and a half of 510 vaping i got the following results:
-First atomizer lasted 3 weeks of vaping like a champ, then suddenly didn't produce much. And nothing i could do brought him back to its original shape.
-Second atomizer vaped for 2 days then suddenly died...incidently at the exact moment the post office was handing me my 3rd atomizer.
-Third atomizer was like "wow" the first week, then suddenly dropped its production of vapor and throat hit significantly...But not enough to throw it away...That's 2 weeks of vaping with it till now.
As for the 901...Well...It has some serious flavor restitution...Way better than the 510...but with much less throat hit.
And...It has this awful semi-gargling sound at the start of each suction, even if the atty is not flooded...then you have to push hard on the draw to get it to work, even if the draw is smooth in itself...yet the battery needs a little harder draw to function, compared to the 510. I think that with a manual battery it would be ok though.
Anyway, with the automatic battery, i kind of solved the problem by covering 1 third of the hole the 901 atomizer has, with a tiny piece of tape...Thus readjusted the pressure that controls the flow, enough to have a more pleasant draw, without cutting much air on the atty.
I think that the hole on the 901 atty is a little bigger than it should be IMHO.
I'm still at my second week of vaping with the 901, and i still didn't decide which of the 510 or the 901 is better....But it will come up soon enough i'm sure.