I noticed a link over on the WiX-Users list for even more information on the .NET 3.5 Client Profile. I've not had a chance to absorb it all but I wanted to share the link ASAP.
Edit: I've absorbed a bit and I'm a little less impressed with this servicing mechanism. It seems that this is really aimed at XP SP2 with no framework. XP machines ( and all Vista machines ) with the framework can't go the client route but must instead get the full install.
Thinking back to my originial problems deploying .NET 3.5 applications, I'm not sure if this will really help us or not.
Also I noticed this little quote from the MS blog
"As is illustrated in the preceding table, the Client Profile deployment is focused on Windows XP SP2+ with No Framework components installed. This platform configuration is still the predominant platform configuration and will continue be so for the foreseeable future."
Ouch. I'm sure the SlashDot and Apple fans would love that quote.