I know this is an old thread, but I guess I have a little to add?
The Envy Bliss, my first e-cig, only ever lasted about an hour between charges. I liked that it was small, and I liked that the light was green, but ultimately it wasn't worth the trouble. In early 2011, the options weren't yet very good.
I went back to their site from time to time, and that's when I read somewhere (?) that the Envy Ego Tank was made by Joye... Interesting since the Envy Ego Tank was 49$ for a 650mah and a 1000mah battery, two attys, two emptys, and five filled cartridges. That's less than anyone else as far as I know...
I ordered one after calling and verifying they are made by Joye and it's been great ever since! The only problems I have with the thing is that Envy sent the two empties without silicone caps and won't sell me replacement caps.
Also, I wanted something smaller to sell my gf on ecigs, but the Bliss and the Nirvana are explained on Envy's site as identical products and I'm not going to buy another one of those, so I ordered up a 510 tank. I dig the tank system, and I dig Joye. Any unless someone offers a better price, I'm content getting the re-branded Ego Tank from Envy. Plus I like their green and black motif...