I had the opportunity to use a 4073a in a shoot last year (on a boom, outdoors) and I really was impressed with the sensitivity it displayed. I'd love to have one in my kit. I second what Jeff just noted above.

You can hear clips recorded with the 4073a in my article As I Hear It - Choosing the Right Microphone

FWIW, I have used this mic for years as several clients own it and I have shot interviews, exteriors and just about everything in between with it.

Very sensitive
A bit thin sounding
Prone to sibilance so if you are recording a sibilant person, be careful.
Built like a tank, very reliable.
Personally I like the overall sound of the AT-875R better at less than half of the price. Keep in mind that the 4073a was designed probably over a decade ago while the AT875R was designed less than two years ago. Technology does change and advance and sometimes newer products that cost much less can sound and look better in our business.

Dan

The 875R has a few drawbacks vs the 4073a to go with the low price point:

1. The frequency response is 90-20 vs 30-20.

2. No low cut filter.

3. The S/N ratio is 74 vs 80. Seems all the good mics have at least an 80 dB S/N ratio.

4. Not long enough for a stout shockmount like the SM3.

5. Not long enough for mid level wind protection and a shockmount. Im not sure how you would boom it, but Im sure the experts have a way.

It does sound pretty good in Dans test, not sure about the real world. Generally, you get what you pay for I believe.