There is no way to tell which model will be your favorite until you try it for yourself. I went from pen-style (too big) to super-mini (better, but mine broke days after receiving) to M401 (the automatic battery would light up my pants when driving or boating) to manual 510 (
almost perfect) to 501 w/ pass
through (flimsy but dang, it works great when it works).
Seven months later my on-the-computer
vape is a 510 w/ passthrough (extras on hand--they are dainty things) and 401 or 510 manual when on the road. Your mileage may, and probably will, vary but for anyone trying e-cigs for the first time I recommend going for a model that feels (and looks) most like an analog. It makes the transition easier and they can opt for something with more oomph later if they desire.
Even with all the models I've tried and extra attys, batts,
juice, etc. I'm financially way ahead of where I'd be if smoking analogs. Now, if someone could just help me organize all this stuff I've accumulated....8-o