I have never been an Ecco user, so that will colour my thoughts.

For me, the greatest advantage of SN is the data based items, so that calculations and aggregate functions can be performed on a set of records. That hooked up to the flexability of setting Field properties makes a great product.

The PIM market is pretty crowded, as is the Notes market. I have a very good Notes programme that I'm not about to change for my general notes/web clippings/etc. I use online PIM tools, and use a Java based Addressbook.

But when the notes are data related (ie not just a web page), I think SN has great potential, and as far as I've seen, is pretty unique. So for example, I'd consider using SN instead of writing my own database (generally in Access) to keep my software records.