A few years ago, after doing considerable research on MTH Z-4000 and Lionel ZW-L transformers, I finally bit the bullet, spent the extra money, and went with a brand new Lionel ZW-L.
Boy, am I ever glad I did. This is one heck of a transformer. Conventional or Command selectable. 4 outputs, each with their own re-settable circuit breaker. A pair of voltmeters and ammeters that work on all 4 outputs. An on/off switch so you don't have to unplug the unit when not in use. The "Lionel" logo lights up in bright blue when the unit is on, just to let you know it's on. And no shortage of power that I have found yet.
Admittedly, this thing (or an MTH Z-4000 for that matter) has way more power than I need for my current layout. But since getting it, I haven't given any more thought to needing yet another transformer. I'm glad I spent the additional money and went with a ZW-L. 
