Well, the aerodynamic advantage is still noticeable, but the difference in performance between an unfaired recumbent and a racing bike is too close to call. On hillier routes the conventional bike will be more at home. It is practicable to add partial fairings to a road recumbent bike. Despite the extra weight, these can offer significant performance gains, even on quite hilly routes. A front fairing also provides weather protection and a tail fairing, luggage space.
Most people find that the best thing about a recumbent is comfort.
Your body is supported over a much larger area than on a conventional bike and your hands and arms are lightly loaded. Consequently, you are much less likely to experience aches and pains, especially on long rides. The lower Centre of Gravity of a recumbent bike and rider means that you can stop more quickly than on a conventional bike. You also tend to get less wet and dirty when it rains as your feet are above the road spray and you can keep pedalling around corners without fear of grounding a pedal. I hear you say.