Eh, I prefer a bit of a mix of those two options actually. I rarely ever look at the main gallery if an artist has folders, as I think it makes it easier to find something specific, like fanart or so.
I don't like it when they try to hide their old art, even if it's bad, everyone has been there. Hiding old drawings makes some people think they have been incredibly good at what they do and start talking about "talent" and whatnot.
Still, the artist does whatever they wish to do, of course!
There is also the "All"-button left if one really wishes to see anything. I think it's good option, although some page numbers would be nice... Oh, well.