I'm considering a switch from Protopage to Netvibes as my start page mostly because of the dearth of snappy widgets available for Protopage. While Protopage has been adding them since the latest version went live, I generally don't find them very polished or useful. However, I've always preferred Protopage's highly configurable layout and, even more importantly, the ability to create custom mini HTML pages. I primarily use this feature to create link pages and I have them scattered all over my start page. Some examples are over there on the right.
Netvibes doesn't have a widget for creating mini HTML pages, which is part of the reason I haven't considered it. However, their Bookmarks widget is very cool and uses a tag system. So I figured out how to import my HTML link pages into the Netvibes Bookmarks widget (which was a pain in the ass!) and then tagged them all. The result means I have to click a tag and then the link, but it's not too bad and will just take some getting used to.
However, I've come to realize a major flaw in using Netvibes: page load time. Admittedly, I have a lot of stuff on my Netvibes start page, but it's no more than I have on Protopage. Individual RSS panels, for instance take twice as long to load on Netvibes. This means that every time I launch my browser I'll have to sit and wait before I can do anything. I'm going to try to slim down what I have on the page and see if that helps, but it could be a dealbreaker. Netvibes, I'm sure gets loads more traffic than Protopage, so the problem may not go away anytime soon.