The also go MUCH faster. Fast enough they can catch up with an aircraft carrier battle group (or screen one if playing defense). They are also fast enough to catch up with most modern submarines. The Virginia class subs were designed to be "easy to operate", which they are relative most AIP submarines, and especially relative to ones that pushed the envelope too far, such as the Collins. Even if one gets a Collins class fully operational, try finding a crew that can operate it to its potential capabilities. The USA did come to the realization that perhaps one shouldn't count on having "superhuman" crews. The top submarines of the world do require near superhuman crews to operate them.
