I think they are very close to one another, except not in price.
That isn't unique to these two microphones. Microphones in general fall into the "law of diminishing returns."
Yes, I do agree that the Church microphones hold their own against the 853 series. They are certainly a better value. However, the 853 is a better microphone all around. Not to mention much more flexible. They have a wider variety of capsules, from omni to shotgun and a wider variety of bodies ranging from lavalier to boundary. The company has a long standing reputation for engineering excellence, tight tolerances and fine sounding mics. I also think the 853 uses a gold sputtered diagram and the church mics do not. Correct
me if I am wrong.
Here is a recording done with the 853U omni capsules:
http://www.archive.org/details/grimace2007-10-29This was recorded with a the UniLine series boundary mics, but it is the same capsule...