Windows Live Mail is the new mail client that will replace Outlook Express on Windows XP, and Windows Mail on Vista. It incorporates numerous enhancements over its predecessors. Microsoft has gone through several evolutions of the client, not least in its name: from WM to WLMd to WLM, and there is also Windows Live Hotmail, another variant.
I obtained the earlier Windows Live Mail desktop beta a couple of months ago and have been enjoying its OE-superior feature set ever since. I have a couple of Yahoo mail accounts set up on it, including the one I use with this blog. However the feature that I use and enjoy most often in Windows Live Mail is the blog feeds list. Since the advent of IE7, feed subscriptions have become possible in Microsoft clients. Having feeds in a different client from Thunderbird enables me to keep all my mail folders visible in T-Bird's interface. In time, it's possible I could move other mail accounts across. It's nice to see this mail client support the T-Bird-like functionality of separate sets of folders for each mail account. The lack of this was a major limitation of Outlook 2003 when using an IMAP server, since these have their own remote-stored versions of all folders, whereas Outlook uses a local Sent Items folder.
WLM installed cleanly and migrated my accounts and feeds across without problems, although the existing contents of my mail folders disappeared, only to reappear in a "Recovered Items" folder. As with WLMd, you are automatically subscribed to Microsoft feeds, but you can remove the subscription. Unlike WLMd, there is no advertising; you can turn off Active Search without having to see the advertising banner in its place. WLM uses the Outlook-like shortcuts list on the left hand side, which cannot be customised, but can be turned into a bar of icons, saving space. Underneath, the options dialog is still pure OE, which is unfortunate given that it is out of step with what the rest of the UI looks like. The options are pretty much the same too.
A big improvement over WLMd is that feeds now update automatically; this function didn't work before. Another big improvement is that it is no longer necessary to have the application sign you into Windows Live each time it runs. You can save the time of that step as well as having to get a Windows Live account. Overall, I'm looking forward to seeing the production version come out, especially for use at some level in our network where a few people prefer fewer bells and whistles than Outlook.
Links to recent WL betas are hard to find; the official Windows Live Betas webpage doesn't list them, even though it is repeatedly linked to from WL software team blogs. Still, you can download the US English version of WLM beta here.