I own a Secondo and think very highly of it. It is a big step up over the original 80w (or so) Unico.
The Secondo replaces the Unico SE but is different to it. I would agree with Dkasab that the Secondo does not have a bass slam of the SE - but betters the SE IMHO in virtually every other area - most notably mid range purity. This is an amp for vocal lovers. Feature wise the volume control was improved (over the SE); the tubes are different and usefully, balanced outputs are added.