WiX v3.5 delivers official support for Visual Studio 2010 and IIS7. The standard UI also supports a quite few more languages (but not all of those) and we simplified the WiX language a bit. Plus there are a bunch of bug fixes in WiX v3.5 that makes this release the best version of the core WiX toolset ever released.
Unfortunately, Burn was again postponed to the next release. Also, it is important to note that Votive in WiX v3.5 does not install side by side with WiX v3.0. This is an unfortunate design issue that we hope is fixed for WiX v3.5 upgrades to WiX v3.6.
I would also like to take a moment and note that WiX releases are speeding up. WiX v3.0 took us something like 4 years to complete. WiX v3.5 took half that time (about 2 years). WiX v3.6 is looking like it will take about half that again (about 1 year). WiX v4.0 will big a major version release (so it won't be half again) but we heard the message about smaller releases more often.
Your praise and thanks should mostly be directed to Eric St. John who almost singlehandedly finished WiX v3.5. Also, Candy Chiang drove the whole release so I could focus on Burn and WiX v3.6. Those two plus the rest of the WiX crew hope you enjoy WiX v3.5.
Happy 2011 and keep coding. You know I am.