My Macs came with iLife '08 but I did have the opportunity to try the '06 apps and everything in '08 to me seems better with the exception of iMovie. They needed to keep some of the video editing tools. They did away with a lot of video effects/sound effects that they should have kept.
I was informed that because of this and the cry from the Mac community they offered iMovieHD as a free download for iLife '08 owners so I got it, now I have all the tools I need.
The ultimate decision is yours. For me I like it better than the previous with the exception mentioned above. Has it changed my life? Not in any spiritual/medical/etc way, but it has made sharing my photos movies easier, then again, don't all the iLife apps do that?
I like it.