I Do.
So I played with the C1 and C3 in my studio for a few weeks... Didn't really do any direct, right next to eachother comparisions between them or any other mics I own. I simply used them in real situatrions. But I came to the conclusion that I wanted to keep the C3 and not the C1.
Now let me tell you how I came to this conclusion...
I noticed the C1 had the presence I like and look for in a "budget" mic as that's not all too common, but it still had the high-end "bite" that most "budget" mics have; which is NOT a "bad" thing necessarily, but just not something I was looking for at this time as I have enough "budget" mics with high-end "bite".
Of course, the C1 had that MASSIVE low-end I actually found too annoying... Yeah, you can move it far enough away for the low-end response you want, but that only worked good in an iso-booth, otherwise I found I got WAY too much "room" when in a live room; good as a cardioid room mic.
With the C3, I right away notice the smooth high-end because it a rarity to find that in "budget" mics. In cardioid, the low-end was reasonably tame. In figure-8, the low-end was too MASSIVE for me again. And in omni, the low-end was nearly just as MASSIVE as in cardioid; which is VERY odd for omni.
I haven't try it yet, but with having so much low-end in omni, I have a feeling it'd work nicely as an omni room mic; which is a very good + for the C3 as a good low-end from ANY omni mic in relation to the high-end when far from the source is pretty rare; let alone for a "budget" mic.
In an iso-booth, I always found a use for it; and for the most part, got a pleasurable frequency response. In a live room, it got rather tubby and I seemed to be achy for more high-end.
So, I found two "rarities" in the C3; one for "budget" mics, and the other for ANY mic. And the price is crazy low, so...