The biggest advantage of the powerpacks that I'm aware of is the fact that you get lines with events that can be at angles. Technically, you can use labels, as already noted, to draw vertical or horizontal lines, but not so much for other lines. You can draw lines at any angles using GDI, but lines like that are not objects and don't have events associated with them. Technically, you might be able to work out an efficient algorithm to figure mouse over on diagonal lines in form mouse move, but that certainly gets more tricky.

It all comes down to what you need from the Powerpacks. The issue I ran into is that tooltips get pretty squirrely with the Powerpacks.

Another question that I'd have is how light lines are relative to labels. Controls can have a fairly heavy cost, and you could easily end up with loads of them if doing something complicated with lines, even if you stuck with horizontal and vertical lines.