After experimenting recording my acoustic guitar with the Behringer C-2s in many configurations I ended up sending them back for a refund. I don't think they are terrible but after comparing them to my Shure SM86, Shure Beta 58, Sennheiser e838, AKG D880 Emotion, Sony ECM MS-907, Behringer B-2 Pro and a few others in my collection they just don't compare in sound quality. They were more sensitive than the dedicated vocal mics and certainly could pick up the sound well. But, have a slightly harsh tone, just slight, and sounded somewhat lifeless, no warmth. But, not really all that bad. It's just that I get a much better sound from any of the others listed above. In fact, for recording acoustic guitar in my room the e838 and Sony ECM MS-907 were probably the best but for separate reasons.
Last week I bought an AKG P170 and immediately could hear a good quality, warm, full range sound. It's easy to move around to find a good spot and easy to post EQ to fit a mix or EQ for solo/singer/songwriter. It doesn't have a low cut switch but that's okay.
To my surprise the Sony ECM MS-907 (stereo/mid-side) mic sounds very good. I've had that mic for some 20 years and had never recorded acoustic guitar with it. I almost did and probably could have stuck with using that alone for my personal recordings. But, it's not easy to focus in on a mono recording when that's all I want. It also has a fairly low SPL handling, which doesn't bother me, and a permanent sharp low cut/high pass at around 100 htz. That said, it is a very clear, detailed and warm sounding. I put it close up to the 20th fret/edge of sound hole and turned it sideways so the left side picked up the high strings and the right side pick up the low strings. Panned them left and right and had a really cool stereo sound. So, I'll likely be putting that one into service more often. Plus, for doing scratch tracks like picking up a singer with an acoustic guitar just to grab a basic song it works quite well.

Does the noise in your head bother me ?