I have heard that some e-cigs are able to deliver a decent amount of nicotine to the user, like from a cigarette, whereas others produce a vapor but the user doesnt seem to get much of a nicotine hit from it.Can anyone tell me what are the main characteristics of the "good" ones (i.e. the ones that I can actually inhale nicotine from)? (apart from the nic content of the liquid). The main brands that deliver decent nicotine (and the main brands to avoid) would also be helpful.Thanks