small world!
If I had unlimited resources I'd buy a pair of KM-84s and be done with it (pretty sure I've mentioned that before<G>).
Turns out my resources are limited.
I have a handful of good small capsule microphones that I like, including pairs of AKG C-61s, AKG C-451s, Audio Technica AT-4031s, and Earthworks SR-77s. These are all good microphones, each does some things really well, none of them are really good at everything.
My hunt continues, and right now I have a pair of WA-84s and a pair of M60s (both cardiod only) that I am evaluating. Again both really good microphones, and again they have their strengths.
Most of the time I am recording acoustic guitars, mandolins, and hand percussion. The M-60s work really well with my rosewood OM but get a little "boom-y" with both rosewood and mahogany dreadnaughts. The WA-84s sound really good with the dreads, but I feel like I am missing some of the details on the smaller guitar. The WA-84s win on the mandolins (one maple, one mahogany), the M-60s, and most of the rest make the mandolins (especially the maple) sound shrill.
I haven't heard your violin, nor your room, so I could not possibly make a recommendation. I can offer my impressions (so far) based on recording acoustic guitars. The M60s seem to pick up a tad more detail, which is not always a good thing! The WA-84s have a more pleasing sound, maybe because they don't get every detail (and mistake)? They are also much more forgiving with respect to placement (a trait for which the KM-84 was praised).
Neither of these is a replacement for a pair of KM-84s. Nor are they a replacement for any thing else really, they are really good microphones with their sound and their quirks.
If you can borrow them both and evaluate them for yourself you will never wonder.
But really, I can't imagine you could go wrong with either model.
Probably not a great deal of help but there are just too many variables to make real recommendations.
(It is a little easier to warn people away from a specific model. While there is a good use for almost every microphone I remember using an AKG C1000 and thinking there was nothing for which it was well suited. I was given one, and now I know why<G>!)