In keeping with the tradition of posting a pencil-to-ink comparison for my process junky brethren, here is a big, fat stack of pages from both Deadpool and Superman.
So, if you look closely at the pencil pages for Superman you'll noticed I tried out a pre-printed perspective grid for some of it. I heard of them from various friends over the years, and dug a few up to try out. I thought it would speed things up a bit, as I tend to spend a lot of time layout out the perspective on my pages, but I found that it really didn't save as much time as I would have liked.
I also think they're a little restricting. If you compare the perspective here to the perspective on the Deadpool pages below (where I did NOT use the pre-printed grid) you'll see that those pages just feel more dynamic.
In the end I think the grids can be a good tool, but don't take the place of just knowing how to draw in linear perspective and certainly does not allow for the freedom of doing it from scratch.
Don't say I never gave you nothin'!