Keeping them in the design lib is great if nobody else will be checking them out. If you are talking about locating them on a server that is fine if your assemblies contain only a few routes in them. I have several projects that have around 2000 components aprox. 200 routes in each assembly. If you try to work off of a server it will crash on you big time. I have been working with our VAR and SW on this issue for some time.