Re: The SM58...
You don't buy a SM58 because it's "good enough", you buy it because it never stops working, and that can be just as important as how it sounds.
Whenever absolute clarity, maximum gain before feedback, stage noise rejection or whatever specific quality is important, there are probably better choices in the same price range, and I have made those choices often, and have a drawer full of dead or otherwise non-usable mikes to prove it.
1. It always works
2. It doesn't break
3. You can depend on it
4. It always sounds the same
5. You can't break it
6. It works
7. It doesn't fail
8. It's a know quantity
9. Nobody rejects it
10. It sounds good enough
That I think covers it.
Did I mention that it always works and never breaks?