hi Richard, whether blown highlights (or black areas) are good or bad depends on the intention of an image and/or taste of course; it has become an issue because digital cameras are much more sensitive than film (where you have a variety of films with different behaviour and varying developing options) in my view blown highlights are bad whenever they are not intended (some postwork even generates them); that's why f.i. for portraits I usually take an exposure bias of -1/2 step in your example I don't like the overexposed clouds while the glass is fine for me; look at my "winter walks" for an intended highlight... (that's also one reason why I appreciate the SR CCD in my S3)

Gerald