I don't completely agree with wv2win about auto switch and two piece devices.
As for the switch: I love the large-button switch on my Prodigy, but I hated the teeny-tiny button on the manual switch version of my 801. It would stick and then it got completely stuck in an out of reach position. The 801 auto battery has never done me wrong. Even though I only drip, I've never had a problem.
By two piece, I assume you mean the cartomizers, e.g., KR808D-1 and the more expensive GreenCig. They are simple and easy to use; probably great for a beginner. No muss, no fuss. The carts can get expensive ... and if you refill them, that defeats their advantage. I didn't particularly like the taste (harsh to me) and the vapor was only so so, but many others (including, but not only, Leaford) rave about them.
BTW, wv2win, check out the new
Protege at Puresmoker - kind of a cross between the Super-T and the Silver Bullet. Looks neat!