I don't doubt that sometimes you can find killer stuff at really cheap prices as well. But rarely. A 57/58 is a simple mic; I don't think it's impossible to make and sell a mic with just as good properties for sub $30 too, using China labor or cheaper etc. Maybe the only real difference if any could only appear 20 years down the line or something, a leaky cap or rusting frame or whatever.
It's more about security, knowing what you're getting exactly, AND also knowing the thing will retain its value even 10-20 years from now. A well kept 58 could be 20+ years old and not appear any different from a brand new one, and still fetch the same price.
So, when you get a good hint and such, why not...could be just as good. But it's always guesswork.
It's much the same with cars; get a car from VW, Audi, Seat, Skoda, it's all the same, same parts, a bit different design, a bit different target groups. Prices can vary wildly even, especially used.
Is a $100.000 Mercedes any better a car in any real terms than a $40.000 VW? I seriously doubt it. Maybe the merc is a bit more polished but they use the same Bosch electric parts and whatnot; and the merc likely has more parts that could break. But when you sell them off, there will be the same difference in price still...an old merc can be pretty pricey still while you can't give away same age VW's.
So, it could surely be that a cheapo mic could perform just as well as a more expensive one.
However, I have owned a lot of such mics touted as great for price, and indeed many were. We sold a huge bunch of one 57 copy in particular. But for whatever reasons, in the 20 years passed, I only still have some Shures and AKG's...slowly got rid of the cheaper copies for whatever reason. Maybe some appeared to be prone to catching the 'pop' from vocals. Some maybe were suddenly prone to handling noise. Some just plain started to sound bad to me in comparison with something else. Some were very directional. On some a switch broke or the screen flew off when it dropped.
But I still have the 57's and 58's I bought in the 80's and they always do the job, never any issues. It doesn't necessarily mean they sound any better than a $30 mic but they've stood the test of time and I know how they sound and how to position them, and there's never any trouble. Holders fit, they take abuse, they work.
So I guess the bottom line is...hell yeah, I'll buy a cheap mic that does the job well any time to save a buck in a pinch. But, when I get a change to upgrade later..it's always been worth it in the long run.
Dee
"When life's a biatch, be a horny dog"
Amps: Marshall JVM 410H w/ Plexi Cap mod, Choke Mod & Negative Feedback Removal mod, 4x12", Behringer GMX110, Amplitube 3/StealthPedal
Half a dozen custom built/bastardized guitars all with EMG's, mostly 85's, Ibanez Artwood acoustic & Yamaha SGR bass, Epiphone Prophecy SG, Vox Wah, Pitchblack tuner plus assorted pedals, rack gear etc. for home studio use.