There are so many factors regarding the "correct" miking of acoustic guitars, that I thought I'd add my few cents worth about some things to consider when talking about mics "working" or "sucking" or "muddy" versus "bright".
The way a guitar radiates sound is different, depending on the note being played. During one session, I had to:
1. Move the mic, depending on the key and style of the song.
2. Use a differnt mic, depending on the key and style.
3. Use aggresive EQ, depending on the key and style.
Just because one particular mic, in one particular position, works great for a specific song, guitar, and player, is no gurantee that it will work great for the next song, guitar, or player.
Any time you get in close with any mic (to where you are in the "near field" of the instrument), all bets are off - the results may be spectacular, or it can sound like pure crap. It depends entirely on the particular song, the specific guitar, the particular player, the specific mic, and the exact mic placement. Change any of these factors (even a little bit) and the sound can change dramatically.
The ONLY "one size fits all" mic/position I've ever found is a neutral-sounding omni over the shoulder of the player, since it avoids a lot of the nearfield and proximity problems that are more common with other mic techniques, and it gets pretty close to what the player nomally hears. But it's NOT a cure-all, or the best method for every situation.
You have to use your own ears and your imagination to get the sound the way you want it. Sometimes it's the over the shoulder thing, and sometimes it's in close. What are you trying to achieve? Here are some things that I think about as I'm trying to get a good guitar sound. It may help you as well:
1. Listen to the player. What mics do you have that will get the sound he's playing?
2. Listen to the guitar. Walk around and listen to find a spot that sounds good.
3. Pick a mic that you think will best bring out the sound the player wants to hear. Place it in the spot you picked.
4. Listen to the sound thru the mic. Are you hearing too much of something or not enough of something else? Can you move the mic a little bit to back off the "too much" and increase the "not enough" parts?
5. Do you have a different mic that might get closer to the ideal sound you're looking for?
6. If one mic is getting "most" of what you want, can you add a second mic to get the rest?
7. Is the second mic causing other problems?
8. Can eq do a better job than adding a second mic?
9. After you have everything just right, listen again to see if this sound is going to fit in with the rest of the instruments. The "perfect guitar sound" soloed may not be the best sound for the song.
10. Don't be afraid to scrap everything and start from scratch if it isn't working. Sometimes, you have to rethink stuff when it's not working, even if it means starting all over again.
Finally, remeber that there is no "best" mic, there's only a range of mics that will work for a particular song, and a bunch of mics that won't. When you can hear "which is which" in your head, you're on the way to becoming a great engineer. Because something worked perfectly in the past is a good reason to at least consider it for this task, but it may not be the best choice for the current job.
Trial and error (and remembering what the results were) leads to learning. Don't say, "that sucks" - say instead, "Interesting, I'll hafta remember that next time I want something weird-sounding".
Every combination of sounds has a potential use. A hollow, phasey guitar sound may be the "perfect sound" for some future recording. If you run across a hollow, phasey guitar sound accidently today, remeber how you got it - it might be great for a track tomorrow.
I like them on other guitars though.