I'll start by saying that the 991 was the most comfortable shoe I'd ever worn.  Based on that experience I decided to go for the 993.  Big mistake.  I first noticed that the arch seemed low, which was a little uncomfortable but I figured I just needed to break them in.  Well, after developing shin splints from a day of walking in them, I looked side by side at the insides of both the 991 and 993, discovering a significant change in the shape of the footbed(not just in the materials, which is what the company claims.)  I've decided that these shoes are unwearable.  Still longing for the feel of my 991, I tried on various New Balance shoes.  They all seem to have this new shape with a very low arch that graciously invites all sorts of injuries and pains.

You might think that this is just me, but about a year ago, a friend who was wearing the 993 noticed my 991 and said that he wished he still had his 991, that the newer shoe really sucked.  I wish I'd listened to him.  In the meantime, my search for a good all around sneaker continues...