Would you believe I've had all three!?
June Taylor - never liked it. The in between plexi is thin enough that if I hit it with the cutter, I'd get a crooked cut. Too flimsy
Martelli - never got the hang of their cutter, which is too bad. As I get older and my hands are weaker and ache, the ergonimic handle might help. As Fizzle mentioned above, you can't see through it, which I felt was a deal breaker.
Creative Grids Stripology - I *love* this thing! I have the bigger one. Have never had a problem with mis-cuts or crooked cuts. I do have to be careful where I put the teardrop (where the blade goes in) as if it's too close to the edge of the fabric, there will be an uncut part near the fabric fold. Not a huge deal, as it can be snipped with scissors if needed. The slots are 1/2" apart, with a star under those that you'd need to use to cut 1-1/2" strips and a square under those for a series of 2-1/2" strips.