Just as a guy never forgets and always appreciates his first love (in my case, Gloria), I believe there's also an affinity for one's first transformer; in my case, a two-throttle unit for my boyhood AF layout and a KW for my adult era Lionel layout. However, the electrons don't care about transformer design/looks, they'll do the work according to laws of physics without complaint.
I never owned a ZW, but its "football in a box" shape is an icon in the O-gauge hobby. My current layout uses a Lionel 135-watt "brick" and TMCC gear; all of it hidden in a handy pull-out shelf under the layout platform. Those modern components are fully functional and very reliable but not "fancy."
Mike Mottler LCCA 12394