Both the Nikon D3100 and D5100 are good beginner DSLRs, and either can be a solid first step up from a point-and-shoot. For most new users, image quality differences are less important than how the camera feels in your hands, so try handling both if possible.

From the community answers, the D5100 is the more advanced option, especially if video matters to you. The D3100 was preferred by some because it costs less and may have better ergonomics, letting you put more of your budget toward lenses.

On lenses, one answer recommends skipping the kit lens and spending the savings on a better lens, since lens choice affects your results a lot and should match what you want to shoot. That said, the best lens depends on your subjects and style.

So the practical takeaway is: choose the D5100 if video is important; otherwise the D3100 is a sensible value choice. Prioritize comfort, size, and weight, and think carefully about your first lens because it can matter more than the small differences between these two bodies.