Well, my mind's made up. I'll be getting a REO Grand, and a bunch of accessories, among them atomizers of various strength.
My decision-making process, in case you care, was this: I read through the recommended newbie threads, all of which were immensely helpful, and got my head around the basics. This took far longer than I'd thought. I had marked down two days in my calendar to "read up on vaping and get a kit" (heh) and came away with two weeks of nightly study, including a refresher course in electrical engineering 101. But at least I now know my volts from my ohms.
I quickly realized that rather than a cigarette lookalike, I'd want the biggest batteries and tanks, hence an APV. My next criteria were, and remain, maximum reliability and minimal hassle, which led me to the Provari and (soon after) the REO. Both get excellent reviews, and looking at the way they are made (and the price, ahem) it's easy to see why. In the end, the encased tank of the REO tipped the scales - I just didn't want to carry around a pack of cartomizers or screw on larger tanks that might leak, bend or break off when I toss the thing into my backpack.
I then spent a long time weighing the relative benefits of variable voltage. Almost all experienced vapers seem to want higher than usual voltage, and a way to control it. This means electronics - but if they quit on you, you can't fix it yourself. So I settled for a mechanical mod, and an assortment atomizers with different resistance; the expectation being that I'll use direct drip or cartos at home until I find the juice/voltage combo(s) I like, then stick with one configuration during the day. I realize that this means more fiddling than I'd initially expected I would want, but one can't (yet?) have it both ways, it seems.
Let me close by saying that I am deeply grateful to everyone who contributed to this thread or wrote a newbie guide. The sense of community and the kindness shown to strangers here reminds me a lot of the Internet in the early 90s. I'm glad to have found a place where it lingers on. Getting into vaping is a real headf- ... a real challenge, and I would have given up on it on day one had I not found this forum, and your advice. And that would have meant continuing to smoke tobacco, inhaling tar and hundreds of other carcinogenic compounds.
So thank you very much.