I bought the swisstool RS, complete with the pouch and tools. I suppose that makes it the swisstool CS plus. Actually the way Vic names the models are really confusing and has no logic...but I digress. I also have the Leatherman supertool. I have used both when I moved house and fixed up a lot of stuff. They are also deployed when I am fishing, camping, etc. I find that the bigger handle of the swisstool is much more conducive to heavy pressure usage. Additionally, I recently found that the leatherman has the tendency to jam it's jaws together when cutting wire - then you have to pull the legs apart in order to open it. That does not happen to the swisstool - not to me anyway.
According to the Vic site, both the spirit and my CS (probably also the RS) have exactly 27 tools on the knife alone. So there's no diff. If I am wrong - sorry. But here the point is really on the handle, yes? So, here we go:
I recently handled the spirit - it is a lighter tool, and the more ergonomic handle design is definitely a plus. I do see your point on the ruler on the handle: more than once in a pinch I have used it as such. However, you really have to draw your own conclusions on how useful that would be - so much so you have to compromise the comfort of the handle. Having spent weeks intensely using both multitools, I can tell you that the swisstool RS handle is going to hurt you (after those weeks of use) - and the leatherman much worse!
IMHO I would not trade comfort for the rule. Reason? When using the rule, the rounded edges, etc. does not lend themselves to the kind of accuracy one would expect or require from a calibrated ruler. Even a rough one. And if its going to be that rough, you can also use a template or a string cut to length or etc., to mark/measure/note the dimension. If its a ruler you require, then you really need the ruler. But the plier function is where such a tool rules supreme and is mostly applied. And to apply it comfortably - you really want a nice handle.
There is another thing: the tool that comes with the toolkit - call it a wrench. In the RS - its just a wrench although it has never failed me. And bless Vic, you can get standard sized bits which you expect to use and fill the magazine supplied with them. Now the wrench - in the spirit - its a ratcheting one! How wonderful! A ratchet is ten thousand times nicer to use than a wrench - as you or anyone would testify. Inevitably the tool gets applied in a really tight spot, and that's where it really shines.
BUT! Do be aware that the ratchet is newish; although I am not aware of complains of its failure, it is a fact that one more part means one more potential to failure. The KISS principle can not be refuted. So if its going to be your primary tool (let's say on a trip) - then I would prefer a fixed wrench. But if it's secondary or backup, then enjoy the luxury of a ratchet while it lasts.
Damn. After all this I am really tempted to go out and buy a spirit now. You guys are really a bad influence, you know? Hope my 2 cents helped.