Hello,I presume that Busway means use of bare conductors run on insulators.The major cons, are they have to be enclosed in a metal box with required IP protection,there will be joints at direction change overs(Joints are week points),is time consuming(first busway supports have to be fitted all along the route and then busways are run on these supports),extensions have to be planned and necessary provisions have to be made to tap(requires junction boxes to fit into the Busways) and lastly additional cost for materials and installation