I'm using a L2 510 with a usb passthrough and love it. I do about a 3 to 4 sec draw and get good vapor and TH. I use the "blue foam" cart mod and get 9 drops to a cart and about 40 to 45 puffs per cart. At 12 puffs from my old analogs, the carts are giving me about 3.6 to 4.0 analog cigs per cart.
Much, much cheaper and I like vaping so much more.
GL - Keep Vaping