I use the color-coded Clover tape makers when I need bias tape. I heavily starch the strips before running them through. Basically I let the iron sit in one place while I pull the tape through. Here is one of the sizes I use:
http://www.amazon.com/Clover-bias-ta...dp/B001W2GL5S/
It's basically very easy, so I'm not sure why people buy the machine that does this (unless, maybe, they have a need for 1/8" strips of bias; I believe Clover's smallest is 1/4"). This is for bias that has both sides folded towards the middle -- used for applique.
I do not use these for binding quilts. I use straight-of-grain strips and do *not* iron them in half before applying as binding; I find the binding rolls better without that extra step of ironing. I rarely use bias binding to bind a quilt but, when I do, I prewash the binding fabric (one of the few times I prewash fabric) and starch heavily before cutting into strips. Again, I do not see the need for a machine to do this.