As regards entry 25 and 27, if you could make the V look more like a "correct symbol" similar to the NIKE logo, that may do the trick. Also, ultimately, the logo would be shown on a white background.
I like this design a lot ( design #79 and 80. ) I'm left handed myself and when I make a check mark, mine goes off up into the left, instead of the right. Can you flip around the "V" and perhapse give it a little bit more of an arch downwards towards the top left hand end of the check mark. Thank you.
As regards #106, can you make the check mark narrower ( i.e. same width as a regular V would be.) also make the top 1/3 of the left hand side of the check mark slant down over the A a small bit.
In #121, Can you make the checkmark go the same direction as #106?, if so, that will win the competition. I want the checkmark to go up left instead of right.