from my experience blogs get indexed very quickly and without any effort if you don't have bad neighbors (some times I end up with the "Just another blog" standard and k2 theme cached simply because Google discovered it before I actually had time to change theme and add content).
G expects blogs to update more often than other websites - if you don't (or use any sort of scheduled publication), the bots start crawling it less and less often.
minisites are better as fire-and-forget (just as itrevor said). each has its strong points, imho.