Tip 6.
Use of fraction (stacked text):
Example: In the mtext editor, Type in "xyz/mno" highlight it then click on button with "a/b" on text formatting toolbar you get stacked text.

Tip 7.
Fractions in mtext 1/2 gives you a vertically stacked fraction 1#2 gives you a horizontally stacked fraction 1^2 gives you a vertically stacked fraction with out the line. the text infront of the ^ becoms superscript, and the text after the ^ becomes subscript All of the above require you to click on the "a/b" button on the formatting bar, of have autostack turned on.

Tip 8.
when editing mtext if you press "ctrl+enter" keys it will exit the editor. A little faster then always having to click the OK button.
Zooming the drawing while in the mtext editor only works in 2006. Does the centerpoint of you zoom not change when you move the mouse around? This is fun.
I have shared few tips in this thread I hope there are plenty of experts over there to share some of their tips.