I am recording fingerstyle acoustic guitar. The human ear is an amazing organ, and a good
acoustic guitar has a very delicate and complex sound. Especially in the midrange. Many of the mikes I've tried have "the highs" and "the lows" and sound "good", but there was always something missing. The word that always comes to my mind for what is missing is "leathery texture". I've experimented with mikes, mike placement, preamps, EQ, room acoustics, compressors....
When the smoke all clears it seems like it really should be obvious that what I needed was a simply "deadly accurate" mike, with dead-nuts-flat frequency response and fast transient response. With the QTC1s, it does seem to be as simple as setting them in front of you and playing. What you hear is what you get. There is no "searching for sweet spots", etc. That's why they say "the right instrument...etc." A mediocre instrument will continue to sound EXACTLY that way (well, you can add effects)
But I will refrain from getting TOO high on them until I have really worked with them a while. Maybe I will find a flaw. I have enough experience with music gear to know that everything seems great when it is brand new. Sometimes the flaws and inadequacies don't reveal themselves until later.
Oh yeah: Flaw #1: They are so hot that you have to turn all your mike PREs down to about 1/2 to 3/4 of their usual value.

Flaw #2: They are omni, so you wouldn't want to use them to keep closely spaced instruments separated in the mix, unless you mike really close. But that isn't on my list of concerns.
Flaw #3: Higher self-noise than most mikes. There is a definite white noise hiss that only becomes noticeable as notes fade away to near silence. Compressors make this more noticeable, and I do like to use a little compression. I use an expander/gate to make this less obvious. That requires some careful settings.
Peace,
Rick