There's a guy named Ken Burton that lives in Dallas. He's a computer troubleshooter by day, but he's also one of the best fingerpicking guitarist/singer that I've ever heard. He plays a 1956
Martin D-18 with a paper thin top, and Ken's voice is wonderfully warm and resonant. He's a joy to record.
When I recorded him the first time, I used an old Fairchild condenser mic, about 2 feet away and forehead high, just kinda pointed down at his guitar and it was a perfect blend.
The next time I recorded him, I didn't have the Fairchild (it was being upgraded), so I tried a whole bunch of other mics on him. To my amazement, the original AKG C3000 delivered a stunning sound and we did the entire album with it.
In the 3 years I owned the mic, that's the only time it beat out all my other mics for a specific application. I wound up selling the AKG C3000 for pretty cheap, since it just sat in the mic closet 99% of the time.
My point is that if you were to hear the original recordings, you'd probably go, "Wow, what a great sound. I want that mic.", but you'd be wrong to buy it, based on my recording of Ken Burton. It only worked on Ken and his guitar. It sounded like shit on every other singer and player I ever tried it on.
These shootouts and comparisons don't mean a whole lot to me, because there are too many other variables that are just as important - especially that specific voice and that specific guitar with that specific placement in that specific room.
Sometimes, I've even had to change to a different mic or a different placement when the guitar player changed key or went to a different picking pattern. What was a perfect combination in one key sounded like shit in another key.
The microphone and placement must compliment what you're trying to record. Sometimes bizarre combinations compliment each other and it all works together. Usually, it doesn't. That's why I often recommend an omni, since it doesn't have as much coloration as other mic designs, and it will give you a more accurate picture of the sound, if the instrument sounds good in the room already.
I understand Alan's frustrations very well when people post clips of shootouts and comparisons; it mainly tells you what sounds good on that specific voice and that specific guitar with that specific placement in that specific room. Will that combination give you the same results with your voice and your guitar with your placement in your room? Probably not. Give Alan or me that same mic in the same room with the same player, and we may or may not get you a better sound than you got for that song.
Should we stop doing shootouts and comparisons? Of course not. For a lot of people just getting started, it provides some frame of reference. Just understand that because a specific mic works well in one situation, doesn't mean it will work well in every situation, for everybody.
There are some good vocal mics that won't get you into trouble on a lot of vocals, and there are some good mics that bring out the best in many instruments. I've talked many times here about the mics I find generally useful, and those are usually mics that don't have serious problems in other areas, making them more generally useful for a lot of applications.
The mics I try to avoid recommending usually have bloated mids, harsh highs, or serious peaks and dips in their response. But even those mics will ocassionally be the best choice for a particular application, just not very often.
Vocals are the hardest thing to get right, followed closely by acoustic guitars. Sometimes a cheap dynamic mic can produce magical results for a particular singer; other times, it's an expensive ribbon mic, or a great condenser mic that works best.
When I listen to other people's efforts, two things come to mind; either I think, "Wow, good choice", or I think, "I'd have tried using ___ in that situation". It all boils down to "Does the choice/results best support the musical statement?" Listening to a shootout or comparison may want to make me try a particular combination to see I can get similar results, but I don't ever think that my combinations will work best in every situation for other people.
For me, understanding how the mic's response and polar pattern affect the sound lets me make intelligent choices beforehand about what things will work best in a given situation.
Even though most drummers use our drum set when they come to our studio, I always listen to them play a bit live in the room, before I choose or setup mics. That's why we have 5 different sets of overhead mics to choose from (and sometimes we'll use seemingly strange combinations of overheads for a particular drummer).
Right now, my son Alex is recording a group, using a Sony C38 large diaphragm mic over the ride cymbal, and an Oktava MC012 over the crash. Those are his choices for overheads for THAT particular drummer.
There are things that you can learn from these shootouts and comparisons - what will work best for you isn't one of them.
The infamous XDR kinda' delivers the goods on that one. 
