The angle iron should work fine as long as it is straight and I would recommend that you put a straightedge across it to make sure. I bought some extruded steel bar once, 3/4 by 3/8, thinking I could use it as table saw miter slot runner. It wasn't even close to being uniform enough to use.
I would say the Bosch first and then the Dewalt but if you plan on using it out of the table and one feels better than the other then I would go with that since both are good routers.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.