I'll echo player30 on that one - I find the 3.7v Mini (or Super-Mini) to be the most versatile. Some flavors may be a little muted (or colder, I guess you can describe it), but I tend to use a 2.6Ω clearomizer most of the time. If I want the extra "oooomph", I've got a metric boatload of 2.0Ω cartomizers. Too bad most of them are Boges, I'm really digging the Kanger-style (horizontal coil) on the Mini.
You can make the 5v play nice with the fruitier/sweeter flavors if you're willing to have different cartomizers/tanks/clearomizers/atomizers in higher Ohms, though. For example, on the 5v, I find 2.6Ω to be a nice sweet spot for some of the more "tobacco" flavored e-liquids, but it fries my Caramel Cappuccino, so I tend to use a 3.6Ω cartomizer for that one.
So it's really, six of one, half a dozen of another. They're all solidly built. Sarah and Jay are always supportive, so you really can't go wrong.