No one mentioned the sizzle of the cartomizer, but to make vapor it's boiling small amounts liquid. With higher voltages, you can't miss it, and it's accompanied by crackles, but with the typical "cig like" PV, it'll still make a hissing sound, though it'll be faint. The other end of a cig does a bit of that too, as it burns.
Not at all to belittle your compliant, as it is a valid "something new" when using ecigs, but most of the people I've seen on here blow right past that difference trying to fix the taste, so if that's the worst of it, I would be that you'll be fine with it before long.