I’ve had a healthy discussion with some of you on this post and we’ve received quite a lot of feedback on Soma’s blog and other places.  Based on this feedback we’ve produced ISOs for Visual Studio Update 2 and decided that for these "”larger” updates, we’ll continue to do so in the future.

You can read more about it on the Visual Studio blog here: http://blogs.msdn.com/b/visualstudio/archive/2013/05/03/announcing-availability-of-isos-for-visual-studio-updates.aspx