She will definitely benefit a lot cleaner voice with E945. Even e935 which is pretty much the same mic.It is supercardion mic and it it's really good on the stage with handling feedback.I am not much of a singer but for now it's my main mic.Very nice sounding. Much, much cleaner than sm58 which for me has that dull sound that you are talking about. It's all in the midrange and I hate it to tell you the truth. Not that it's a bad mic at all. But, there are several better mics now days.
She should go and try several mics and see which one is good for her regardless the price.

Eric M80 is a great mic.