Just chiming in to share my experience. I hope it'll be of help..
I bought the Eastwood tubing bender last summer with the intention of making my own cage. My first time using it the 1.5" die snapped in two while bending 1.5" x.120" DOM tubing. I was able to complete my hoop supports after drilling and bolting the aluminum die back together- going very slowly.
The second time using it the 1.75" collar stretched apart like butter trying to bend 1.75" x .125" DOM tubing. After rebuilding it with stronger material the bottle jack just didn't have the power to bend the tubing. My neighbor had a better bender and he helped me make the cage.
We made it without any CAD software, etc. We followed the procedure listed here:
http://www.pirate4x4.com/articles2/tech/bendin_tube
It was rather easy to do (just make a template of your bender with a piece of scrap material and a cardboard template) and we came very close in accuracy. I'm talking less than one inch variance for the main hoop at the bottom. The cage more or less fell into place in the car. You can read more about it, and see pics on my build thread.
If your cage will be less than the material I listed above I think you could get away with the eastwood bender. If you are using the same or strong,er definitely get something else. Also, it's only rated up to a 90º bend, but with material spring back you will get a little less.
Eastwood did replace my broken parts, btw.
I hope this helps.