Homebrew PCBs

The reason for the negative photoresist is cost. I can buy the 
photoresist in a spray-on bottle MUCH cheaper than I can find the 
positive resist.  I can also buy clad boards cheap on E-Bay.  So, 
using the negative resist is the cheapest way for me to go.   I make 
a lot of mistakes on layout and such (and of course learning) so I 
end up making some boards many times before getting it right.

If the pre-treated boards were cheap enough, I would go that route 
right away, but I am just trying to save a few bucks.

As for the scaling issues with the laser printer,  it has to do with 
scaling in one axis versus the other.  I forget which way it is, but 
for example the 11" side needs to be scaled and not the 8 1/2" 
side.  So, rather than fight that, I would prefer to go with the ink 
jet for the same reason others have stated - very high accuracy.

Thanks for all the help and suggestions guys!

Chris