As others have said the XS 5.5 is a nice boat. Very dry, nicely turned out, and handles well, although in my case its aeronautical abilities were often tested; on many days out more so than any hydrodynamic qualities
The only very slight issue I had was slow speed handling; at very slow speeds it would wander slightly. In all practical senses it was not a problem, just meant a little more working at the wheel when trolling. Might just have been the 90 Opti I had on the back? Aftersales service is also very good.
The smaller XS's (5.4m and below) are less beamy than the bigger ones.
Have you considered some of the smaller Ospreys? The smaller ones seem to have the same sure footed handling displayed by the bigger ones in the range.