The X has a very efficient wing and in combination with its RR engines it's capable of flying fairly fast (up high though, if you're not afraid of radiation) at a surprisingly low total fuel flow. It's a good-looker, you're the fastest pretty much on any ramp in the world (except for some military ramps, I assume) and it's quiet, too.
But: costly to operate, complex (lots of CAS messages which turn out to be nothing, but until you find out, you already had some technicians working on it for a while...), cabin and baggage compartment (not accessible in flight) way too small for this class of airplane and sometimes a handful for the unexperienced aviator.