I prefer tillers as they give you much more feedback on the boat's steering and trim. You might want to note that some of the largest racing boats are tiller steered, not wheel steered.
Tillers are far simpler, less likely to fail, and easier to repair. They are also easier to rig with wind vanes and autopilots in many cases.
Also, the design of most tiller steered boats has a much better balanced rudder.
Tillers do take up a fair amount of cockpit space, but so do wheels. Wheels can also block access across the cockpit when going forward or aft. Tillers, when not in use, can be tipped up and then leave the cockpit essentially clear, most steering wheels can't be moved out of the way.
If you're going to be living aboard and sailing long distances, there's a good chance that you'll be spending far less time at the tiller, using some sort of self-steering mechanism.