For me, it depends mostly on your tools and individual working style, but for the record I've never experienced any qualitative difference employing either style of printing. That may be because my exposures are always quite lengthy, any small differences in the amount of light delivered to the paper being ultimately negligible. Where it can make a difference is in the ability to keep track of dodges (particularly) and burns incrementally (i.e., 10 x 6 secs (total exposure) – 2 x 6 secs (dodge first area) – 1 x 6 secs (dodge second area) + 15 x 6 secs burn, and so on). Combined with a footswitch for the enlarger, one never needs to interrupt the process, or take eyes off the print during exposure.
Originally Posted by fralexis