My vote is drill press and forget the mortiser for a while. The drill press
is a much more universal tool in the shop.

Having used a Delta mortising kit on another person's machine I would bypass
that option too. It did a fairly good job of cutting mortises the first few
times, but after initial dulling of the bit, the drill press handles were
way to short to cut easily. A bigger problem is setup/teardown time and
having the machine tied up for one purpose. By the way, the kits don't fit
all drill presses.

Your can predrill or bore a couple of small mortises on the drill press, and
clean them up with chisels, in about the time you spend setting up and
tearing down the kit.