Hi. I have been looking for mini amp recently. I decided to get Marshall MS-2 amp. From what I discovered, it seems that there are three types of them, "normal", Classic and this R one. Now, I know what's the difference between Classic and this "normal" one. But I need to know what is this "R". From what I noticed, it's for soloing, more overdriven. Am I right? And could you give some opinions about them? (sound in general, not the speaker because I am going to play them on headphones anyway)
MS-2 is black,
MS-2C has a cloth grill in grey (classic),
MS-2R is red.

I'm afraid that's it, as far as I can tell.
They are useful as desk ornaments.

For anything to do with playing guitar, there is a better option.

If you're going to be playing through headphones, you'd be better off getting a decent multi fx unit (e.g. Zoom G3) or even a Vox AmPlug.
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I had one of these, it's a bookend now. They're great as practice amps because even with distortion you hear every mistake and accidental noise. For anything else, all I can say is I wouldn't use it myself.