I've been using the Windows Live Essentials Wave 4 beta for a while now and continue to be impressed with its pieces, especially the new Photo Gallery and Movie Maker.
One thing I've heard lots of complaints about, though, is the new installer, which consists of a small stub (roughly 1.15 MB in size) that then downloads the much larger main installer file and installs all the components automatically. Here's the download link:
Windows Live Essentials Wave 4 Beta
Notice anything missing? Unlike previous versions, there's no obvious way to download the full installer files so you can install on multiple machines. But it's there if you know where to look in the Windows Live Solution Center:
Windows Live Essential Offline Installer links for Wave 4 Beta
The page has links for the full setup files (wlsetup-all.exe) for English, Spanish, French, Japanese, Dutch, Portuguese (Brazil), and Chinese (Simplified). Oddly, the links aren't clickable. You have to copy and then paste them into a browser address bar to begin the download.
The other change I've noticed recently is that the web-based installer now offers the option to choose which programs from the Essentials package you want to install.
In previous builds, every program was installed, including the Bing browser toolbar and Family Safety. Although you could go back and remove the unwanted programs, that was a needless step. It's no longer required.
If you've used the Wave 4 beta, please leave any feedback in the Talkback section.