the three main problems with the gsl are 1) battery life - this thing has a small, weak battery 2) carto cost - around $3 per carto 3) proprietary threading. the carto cost can be solved by refilling them. that will decrease the cost tenfold ~$3.00 to ~$0.30. while i no longer use this device, i still have it and i gravely regret not keeping the empties because i now want to refill them so my gf can use it. i could bite the bullet and buy another 5pack for $14 one time so that i can refill em but i know that $14 can be better spent at hundreds of different places. as far as battery life, as long as you're at home or at work, its not a huge problem, just charge it when you aren't using it and all is well. as far as the threading, you're stuck getting their cartos. and strangely, ordering them online directly from their website costs even more than just picking them up from a smoke shop. i do not dislike this brand since it got me off cigs but those three issues do make it a less than desirable kit. let me reiterate, do not throw away your empty cartos!! even if you are not currently refilling, you probably will at one point and like me, YOU WILL REGRET not having the empties when you get some juice.