From my inital checks it looks like Forbes is the only reader that has opted not to ask you to register to use it. This is interested as I discussed in my presentation at foo camp. The web has set a precedence that you will be provided information without providing an identity and hence most newspaper websites don’t require you to log in. By providing a reader with a richer user experience the papers are able to request an identity (people are used to providing this for client applications like itunes, IM and email). The advantage here is that the papers are able to deliver more targeted advertising to their readers. Forbes appears to have gone against this trend and provide the data to the reader (no identity required).
From my initial investigations it still appears like the Times Reader is the most feature rich (with advanced search, note taking, emailing and saving or articles).
That said there is a great new accessibility feature in the Daily Mail called “Speak this article”… this goes further than the news in pictures feature of the times reader.
The Seattle Post-Intelligencer also released a sidebar gadget (above) to launch the articles but compare that to the TVNZ and nzherald ones… IMO it needs a bit of work!