How would they compare to a quality drill press?

They *should* be better than a typical home drill press, but
probably no better than a radial arm industrial drill press for serious
work. (But the odds of having the power needed to run one of those are
pretty slim in a home shop -- or the space to mount one -- or the
ceiling height. :-)

I've got a radial arm drill press in my garage. It does use as much floor
space as a milling machine. Its set up to be moved outside for drilling on
things like backhoes, loaders, etc. If you've used one of these you can't go
back. Everything else seems like a joke.

Karl