Ah ok, I still figured with as small as a leveling is it would be spacers. A spacer is a spacer?
For me, the best is the easiest and cheapest. For a leveling kit that is. Full suspension lift is different. Some people get all caught up making what should be simple very complicated.
Kind of is, kind of isn't. I agree that spacers can be used on a 2500/3500 in the right application. Heck, I have them on my truck to add to my lift. But that still doesn't make them the best way of doing it if there is another option. However on a 1500 spacers often lead to more issues than not as they allow the suspension to overextend because of the design of the IFS system. When the suspension overextends it can cause the ball joint to pop out of the upper A-arm which a number of guys have had issues with on the 2013+ 1500's. But that's a different story.
On the new 2500/3500's with radius arm suspension spacers aren't as simple as they used to be either. Straight spacers will cause the front coils to warp significantly. If spacers are used I highly recommend offset spacers to help limit that warp and keep the spring oriented where it should be to work properly with the radius arms.
Spacers also do often lead to a slightly rougher ride than stock and can give a few other small issues depending on the spacer brand and application. At the end of the day full leveling coils are a better option as they address the issues better and can definitely increase ride quality over stock which is a big plus in my books.
I understand where you're coming from in that. But you have to remember that a leveling kit is still a suspension lift. You're still changing the front end components and geometry and asking things to work in ways they weren't technically designed for. So there is still more to it than that. Especially if you want good quality.