Well, the CR will give you a more specified use, as in it is made to do one thing, moderate to pretty fine detail while being able to spray thicker stuff. The CS, however, is a wide range tool that does a variety of applications and sizes well. The CS will spray higher volumes, but the CR gives you slightly more detail.
I would go with the CR, but it's really a toss-up if you ask me.
Get whatever's cheaper, but if it's only by $10 or less, go with the CR.
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