I've used Thangles in a buck-a-block program at the LQS, which
is sponsored by Thangles. For 12 blocks using strips fir piecing,they were fine. I can't imagine using them for dozens of Hst's - just too much time lining up and pinning. However, I so like pressing the paper on to keep the shape.
I've not tried the other methods except the ultra easy and free matching two squares, pressing them together and drawing the line. Frankly , the smaller the triangle the less likely I am to draw the line. The other option is to prop your feet up and mark the line on the reverse of all the light square while watching tv, then match them with the dark squares.