But why not just compare the 'average' mics with the higher-end mics in the same location, because in that case the Schoeps are going to blow the AT853 and the other comparable mics away.
I actually did EXACTLY that - I recently taped a show with two rigs: An arena show, with my seats rear-stage, between the stacks. Ideal location.
1. AT853 > attenuator > Microtrak2496 (mic in) 24bit/44.1
2. Schoeps MK4 > CMC5 > Sound Devices 744T (24 bit / 88.2KHz)
The mics were mounted right next to each other in a hat used for stealthing.
I can tell you with absolute certainty that while the Schoeps do sound better, they don't sound 10+ times better, which their cost would suggest. So I'm not necessarily looking for a major upgrade, and I'm certainly not looking to spend Schoeps or Neumann money. I was hoping for something in the $500 - $600 range that would add some depth and finer detail that the AT's can't quite muster. The law of diminishing returns, as someone quoted.
So okay, I'll accept that I don't have a great alternative and enjoy the tapes I get with this wonderful gear, and remind myself that "field" recordings this good were'nt even possible very many years ago.