I think a lot of the speed issue depends on the type of peep youre using. The ghost rings definitely excel here, but I still find the traditional leaf type are faster for close up work. As the distance opens up, and time is less of an issue, the peeps do offer more precision. If youre trying to shoot, small aperture, NM type peeps (M1/M14, etc) close and quick, its a lot slower and almost to the point of distraction. I think its actually easier to just shoot over the tops of them then, instead of trying to actually use them.
As far as the older receiver type sights, Ive had both Lyman and Williams receiver sights on a number of rifles, and while they work well (best for me with the aperture removed), I dont think they are as robust as some of the newer ghost ring type sights (or even my Aimpoints) for rifles that get used for things other than the bench, target range. They were pretty much the only game in town up until around the 80's or early 90's, and then things like AO/XS started showing up, offering a better alternative.
One thing that has always annoyed me about the older receiver sights, is the way stuff gets caught up in them when youre crawling through stuff. They arent exactly "snag free".
Another thing I discovered with the newer guns, like Winchester lever guns, they no longer drill and tap the side of the receiver for those older type sights, and require a gunsmith to accommodate them. The older Winchesters Ive had/have, came ready for them. Now days, the little ghost rings use the rear set of scope mount screws on top of the receiver.
Zeitgeist - The movie
Zeitgeist - Addendum