One of these has come up for sale locally. I already have two enlargers, a durst M601 and a Durst L1000. Both of these are condenser enlargers... How is this enlarger in general? Is it nice and sturdy? I have no interest in printing color, but I'm wondering how beneficial the diffusion head would be compared with the condensers? Also, how easy is it to select the paper grades with the color head? Is it tricky to compensate for the exposure?