I don't have any matching types of LDC's so I use what's been given pretty good reviews around here, the mxl 603s a.k.
a mxl 991. Not a matched pair, but mine are decent.
they are small diaphragm condensers. Someone else can fill you in on the sublte differences between LDC vs. SDC on acoustic guitar, something about realism.
Since I got one type of mic at a time, b/c I'm new to all of this, I decided to get the more flexible b3 since I can play with the the 3 patterns available on it. If I knew in advance that I wanted stereo cardiod LDC for something, then I'd get 2. But not knowing enough to make a decision like that, I got one mic at a time. So since the mxl991 came in a set with the 990, for only $100 at the time, I figured, more mics to try. When I heard the single 991 on my acoustic and liked it about as much as the Oktava mk012, I went out and got another set of 991/990.
So when I wanted to try out a Studio Projects mic, I went with the low cost one, again, but decided that for only around $50 more, I could get something I could learn about patterns, since at that time, I had no multipattern mics.
There's one more thing that is the lazy factor, or convienece factor, and that's the smaller mic and smaller mount for the so called, 'pencil' mics are just easier to deal with, aim, mount is easier, and they're usually lighter and that might play into why I'm using them for aiming at my acoustic guitar too. In my very tight home studio space, that can be a factor, but luckily, I really like the sound.
I can afford another mk012 now, but with the changes in that product, I'm not sure I could get the same one, I have one that is supposed to be the Russian one. I really do like the sound of that mic and I'd consider another for a pair, but ya can't have it all, so I'll do w/ my 991. One is acting up on my now, btw, and I have to do something about it before it gets louder, but they've been good so far....
I have as backup, the two 990's I got and they were pretty good for x/y pairing and easy to mount on the 3 to 1 stand adapter. I'll have to go back and listen again to them at some point.
That's the method to my maddness, HTH.