mini-REVIEW (I own a 4100 and a SCX-4016)
The 4100 has inferior scan quality and is a little slower (15ppm vs 17ppm.)
Although they are very different printers, they are priced identically at MSRP and usually can be found within the same market price range. I use Fry's as an example, where both printers sell for $199.
I would recommend spending the extra cash on the SCX-4016 because of its refillable toner/drum unit (which has a life of at least 5 refills or ~20,000 pages!) and its marginally faster print speed.
The 4016 is a larger unit, with the same footprint but slightly taller. The height allows for a more advanced scanner, which exceeds the stated and realistic output of the 4100.
I'd put the 4100 in a collage dorm room because of its size (its small) and the 4016 in a home office or small business office, since it is rated at 10,000 pages per month output.