I've had one Prodigy for a month or so and one for a week or two. Use BE-112 atomizers (pen style) exclusively and have had no problems at all. Both devices got a well used (3-4 weeks) atomizer transferred over. The first lasted another 2 weeks or so and the new one that replaced it is going strong. The newer Prodigy still has the atomizer that was transferred over.
I hold the button 2-3 seconds at most. I can't imagine holding it 5 seconds with a 901 (I don't like the 901 anyway, but still) the hit would be too harsh for me. Funny thing, I used old "real" li-ion cells in the first one so even though they're old and don't charge as high as they should (come off the charger at about 4.08V) they're stronger than the default cells. Right now I'm using the old 3.7V cells in one and 3V primaries in the other while I wait for some new LiFePO4 cells to come in. I'm going to try the Powerizer ones out of curiosity.
I hold the button 2-3 seconds at most. I can't imagine holding it 5 seconds with a 901 (I don't like the 901 anyway, but still) the hit would be too harsh for me. Funny thing, I used old "real" li-ion cells in the first one so even though they're old and don't charge as high as they should (come off the charger at about 4.08V) they're stronger than the default cells. Right now I'm using the old 3.7V cells in one and 3V primaries in the other while I wait for some new LiFePO4 cells to come in. I'm going to try the Powerizer ones out of curiosity.