The Perfections are more silvery and less shiny. Longer in general and not as round of a hoop.

Here's a picture I posted previously:
viewtopic.php?f=6&t=67450&p=360805#p360805

Never have used Perfection guides. I have used most of the Snake Brand iterations and would highly recommend the Universal guides. As you noted, they have a rounded bottom as opposed to the typical flat bottom and have found they are so much easier to mount because of that and the quality of the foot finish (filing is usually unnecessary.) I prefer the eco lite wire guides as I build mostly lighter weight rods.

Thanks all, this has been very helpful.
Dusty used Snake brand intermediate guides, but I must ask him which "flavour" of Snake brand did he whip on my rod.

The black nickel Snakebrand guides have a look very similar to the old tungsten steel guides used on bamboo rods. I prefer that look over hard chrome -- but that's just me.

--Rich

Oh no, I see you were wondering about my take on this. How long lasting guides are--even of the same brand--is a variable of the size, number and spacing on any one rod, of the fly lines used and the mineral fines in the waters fished most often. As just one angler, I wouldn't be able to account for those variables on my own rods, let alone guess them out among brands--if I could remember what brands I had on my rods.

Dressing the guides before mounting isn't a factor to me. I just do it as need be. "A lot," "a little," or "none" is inconsequential on any one rod build. I do make sure the feet are straight and not bowed up or down. So I might bend one a bit.

I prefer small guides and the more oval shape, rather than rounded. I want the line in a line parallel to the rod and close so there is no slop. This isn't as much about casting but about line control in fishing. I have excellent--too good sometimes so as to be distracting--peripheral vision, so rounded guides that let line bulge left or right of the rod in fishing position say "slack" to my eye when I want quick tightening to swim the fly, twitch it over a couple inches, retrieve or mend, or to set the hook. Get those guides and line bulges out of my eye; all I want is the line of the rod and the tip top and a straight line under the rod, barely noticeable. Now I know where the fly is and what it will do if I nudge the rod, strip 6 inches, and so on. The narrower loop seems to hang and center the line for best control--and provide the peripheral vision feedback that is sort of automatic to me.

But that is to my eye, "studied" in fishing. I will notice line bulging into oscillating postions (left or right of the rod held in fishing position). I would rather swat black flies, but whether this matters much or should to anybody else, I can't say. It is kind of like what color/style/size bead on a shotgun; many have a preference, yet if the bead is removed, they may not notice for quite a while. Eventually, they will, and it will drive them nuts until the bead is replaced.

So I select guides by shape, not brand, chosen from what I have on hand or whatever looks about right if I need to buy some. I always get extras. I already can't remember which is which in shape by brand as nicely illustrated above.

Different for a custom build unless someone has a distinct preference. If not, I'd rely on the builder's judgment for the particular blank, whatever brand or combination of brands the builder thinks suit the rod and the fishing intended.