IF your looking for one the size of a cig I would pick dura-c or 501. I personaly don't care for njoy. The NPRO cart life is just too small. For the pen style You can just get one from someone like puresmoker with a lot of extra parts for cheaper. Plus they charge way too much for there carts. Thats what made me switch. IF you are a serious smoker. Get one with a passthrough with a batt pack. Or Screw Driver