Among recumbents there's a wider variety of design (in terms of the rider position) than there is for upright bikes, and the rider position has a major impact on overall aerodynamics. For the same pedalling effort, some recumbents would be considerably slower than an upright, some will be about the same and some are considerably faster.

Just about ALL recumbents are more comfortable than an upright bike however, so a lot of people riding recumbents are in it for the comfort, and they don't ride aggressively. ....And for the same reasoning, someone interested in competing in sanctioned bicycle races isn't usually drawn to recumbents, because there's generally more races held for uprights.
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