I've never been a fan of Microsoft's proprietary 2D barcode system. With the latest news that their tag reader and creator will support QR codes, it looks like the writing is on the wall for the multi-coloured blobs.
Further evidence of this can be found on Microsoft's latest XBox poster which contains a rather prominent QR code.
Here it is in more detail.
When scanned, it goes to a Google URL shortner!
If Microsoft's own marketing department doesn't have faith in the MS Tag - or their own QR creator - why should anyone else?