All I use are autos. I need an automatic as much as I need a high strength nicotine to keep me away from the cigarettes.
By far the best automatic I've tried is the Echo. It's a fat battery similar to an eGo, but it has a flat top with a "sealed" 808 connection. It has a very good automatic switch; unlike other autos it immediately shuts off when you stop puffing on it and will turn on immediately even after it hits the cut off. You can find the Echo at Mountain Vapor, Northwest Vapor, Cropduster901, SmokTek and NHaler just to name a few. Mountain Vapor has the best starter kit, with 5 cartos or 2 CE4's. Mountain Vapor also has an automatic eGo which I am told is just as good as the Echo. Unfortunately with the Echo, you're stuck with the cartomizers or CE4's designed for it if looks matter to you. If not, then any 808-threaded device will work just fine on it.
I have both the Echo and an X2 from Smokeless Image; the Echo definitely has an easier draw and a better switch, but the X2 does have cone threads for aesthetics.
When it comes to minis, the eRoll has become very popular recently. I haven't tried it, nor am I likely to. I just don't feel like messing with atty+tank systems on the go, which is odd because I exclusively drip. The PCC issue is more pressing to me, though that can be worked around.
I absolutely love the Sidesho by Modern Vapor, though it is the only super mini I've ever tried. It has a nice easy draw and the PCC is very nice. However, since I drip on autos I do have 2 dead batteries inside a month but only one of which I can definitively say was caused by over-dripping. The Sidesho is the same size as the Blu or the Volcano, but better quality. And they offer blank cartomizers, the only company with a battery in that size range who does so that I have found. I do have a Joye 306 kit on the way to compare.
I wouldn't necessarily recommend the Volt. At least for my preference, I prefer an easier draw than what I've encountered with their batteries. They are a quality product though, and they do have great service. Of the standard minis I have tried, I actually really like the Fin. It's a cheap brand that you can grab from WalMart for about $10.00. I wouldn't recommend their flavors, but they have the easiest draw of the stick batteries I have tried and replacements are cheap.
If you want a pipe-like experience, I haven't heard horrible things about the 601-C. It's an automatic e-pipe that takes 510 cartomizers.
Good luck.