Yep, you'll be responsible for painting and assembly (or rather, you GET to assemble and paint them!) - these minis are like tiny model kits.
As far as what the figures will look like, there are two kinds of shots Prodos has put up - CG renders and actual model shots. The most recent one labelled "Procast" at the top was an actual model shot, to give you an idea of the difference between the two. As an avid wargamer, I can tell you that in terms of sheer technical proficiency, the sculpting on these models compares very favorably to most of what's currently available from other companies.
Now, for painting and such - it's not necessarily for everybody, but it's for a lot more people than think it's for them. I've had a lot of people tell me they don't think they have the patience, or the skill, or their hands are too shaky, or whatever, but take it from a complete stranger on the internet who claims to know what he's talking about - it's all smoke and mirrors. I have very shaky hands, certainly not much skill, and I only started seriously painting about a year ago, so I don't have a ton of experience, and yet this is my most recent Warhammer project:
There's a few very simple techniques you can learn from anyone who knows what they're doing, and/or from online tutorials that can get you going with a bare minimum of trial and error. Of course, as with all things, there's no substitute for experience, but the only way to get that is just to dive in.