Recumbents take the pressure off the two main points of contact on a traditional diamond-framed upright bicycle–the butt and the hands. They do this by taking the majority of your weight off of the small point of contact with your rear end and distributing it over the much larger surface of your butt and back. Being in this more sitting/reclining position also removes the bulk of the pressure off of your hands, wrists and shoulders and places your posture in a position that allows for eyes forward, rather than eyes down, means of riding. This new position takes the stress completely off your neck and shoulders and for the cycling tourist, that means that you’ll be able to spend more of your day taking in the scenery you’ve worked so hard to travel through, rather than just being oh-too-intimately aware of the pavement beneath your front wheel.
Because the reclined position of the recumbent bike or trike has less frontal surface area presented to the wind generated by riding, the recumbent needs less power to one degree or another to ride on the flat or downhill than a traditional bike. Most will agree that recumbents are usually slower uphill than a regular bike, but the degree to which some recumbents punch through the wind on the flats and downhill can be dramatic! Traditional bike racer types may perceive a low racer recumbent bike or trike as a cycling alternative best suited for the timid or faint of heart, until they find themselves pasted like they are standing still on a long downhill.
The author’s personal experience of recumbent trikes is more akin to a street luge or a human-powered go-cart. The majority of your pedaling energy goes toward overcoming wind resistance and the more cleanly and comfortably you can move through the air and down the road the more miles you can cover in a given day and arrive at your destination painlessly.
Another factor that should not be dismissed is safety. Long wheelbase recumbent bikes are much less prone to doing an endo, that is, going over the handlebars. The most serious injuries on a regular bike result from forward impacts, resulting in head, neck and collarbone fractures. With the feet-forward position and the frame and/or crankset in front to absorb the impact, recumbents clearly are the safer choice. Trikes offer even greater safety due to the inherent stability of three wheels on sand and/or gravel and can hold a precise line at the edge of the road. Because you don’t need to balance a trike, there’s no wobble. Climbing a hill on a trike also means that you can go as slow as you like, or even come to a stop if need be to take a break. (This is a real plus when climbing a long, steep pass with a full touring load!)
A recumbent, like a traditional bicycle, is a human-powered vehicle. Human-powered vehicles exist to take the power of your muscles and convert it to speed, a speed greater than that which can be achieved by walking or running. Which machine you use is relative to where you ride. A traditional bike has a slight edge where there are a lot of steep climbs, or stop-n-go urban traffic. Everywhere else, however, when you factor in the comfort factor, the nod goes to the recumbent corner.