Other than making sure that the threads fit, is there any difference from one clearomizer to another? Also, while Googling around today, I saw wickless clearomizers. Do they work as well as the ones WITH wicks? Seems like they might be easier to deal with. I just bought an itaste v3 and it comes with 5, but I figure sooner or later I will need to replace them and want to get what will work best. Thanks for any help!