HP lasers have faster warm-up times than Samsungs and they tend to be less noisy when printing. I picked up a Samsung ML-1740 because the price was great and it actually produces very sharp prints. The replacement toners for it are $80 and yield 3,000 pages. The Samsung also has an on-printer "Toner Save" button that forces the printer to print a bit lighter to save on toner. The only thing I don't like about the Samsung is that the Mac driver is half-assed (it doesn't have near the flexibility of the Windows driver). Other than that, it's a terrific little printer.
I have a friend with the HP LaserJet 1012 and he seems to love it, but I think I prefer having the Samsung's paper cartridge versus the top-loading "L" mechanism on the HP 1012. Loading in thicker stock (like envelopes) isn't much of an issue on the Samsung either, because it also has a manual feeder that works okay.
A vote for the Samsung.