Not my review but a review off musiciansfriend....
I take no responsibility for what was said in this..
I also own the SM58 and XM8500... and have noticed the same points.. but hell im only 15 years old.. so dont believe ne thing i say..
"I did a direct comparison between
the Behringer XM8500 and a Shure SM-58 by recording a few sentences into each mic to a DAW. The mics were unplugged and switched in the same mixer channel between test recordings to eliminate the possibility that one mixer channel sounded different than the other.
I take back the comment that the Behringer sounds identical to the Shure. It actually sounds a little better. The level of the Behringer is a little hotter, and it has a slightly richer low-end with slightly better high end extension. The midrange "presence peak" that the Shures have is also present on the Behringer, but the Shure sounded a little thin when directly compared to the Behringer. Test was performed both with and without a foam windscreen with the same results.
Also, to make sure that the improvement in sound quality we were hearing was not due to the boost in level, levels were later adjusted to the same normalized output. The Behringer mic still was slightly better.
As a further test, I DJ-ed my morning radio show entirely through the Behringer mic instead of the SM-58 we usually use. The other DJ's also used it and preferred the sound of the Behringer mic.
Bottom line: SM-58's a good mic. The Behringer is a little better yet."