endo is not shareware anymore.
Please read this information from the developer's blog:
"I have decided to make endo donation-ware as I just don't have that much time to spend on both ecto and endo. Since ecto is my flagship product and the one app that has lived from when I started writing Cocoa apps and the one app in use by so many users, it deserves most of my coding attention. Aggregators for Mac are a dime a dozen and they're all good quality. endo will remain software under active development, but it will be of less priority than ecto. It's likely I'm upgrading endo as a 10.5 only product at some point. I have always considered endo has an alternative aggregator, one that approaches news-reading differently from the rest. I use it daily and am pleased it has gained some kind of cult-status with a sizable group of followers."
Maybe the administrator of endo in I Use This could update the information about the application...

Not sure it's worth the money: the UI is "different", but not more. It's not much better than already mentioned Vienna and doesn't compare well with other shareware RSS readers. Maybe new versions would be better but right now it's surely not "fantastic".

Vienna has had support for posting to del.icio.us since 2.1. It directly sends the information you want to Pukka and/or Cocoalicious.

Vienna is a nice application - and free/libre to boot. If it works for you, use Vienna. I'm not so sure Vienna is more feature-rich: endo is more configurable, has extensive scripting support, integrates with blogging clients, and has direct posting to del.icio.us. It's one of the richest and most flexible feed-reading experiences out there. The developer is very responsive, too.

Worth the cost, especially when you get the package with ecto in it.

How is Vienna more feature-rich? I'd use it except it doesn't have del.cio.us bookmarking or blog posting abilities.

Does this really need to cost money when Vienna is more feature-rich? I'm confused why Mac RSS aggregators always seem to be shareware.