Can you elaborate on the differences?
Sure,
First the "puffball" web special is missing a waist draw string to tighten it, whereas the micropuff has one. The biggest difference is the stitching in the baffels. The micropuff has horizontal "tubes" while the puffball has more like quilted blocks. There is additional material on the shoulders of the micropuff, where you would have your pack straps.
After ordering the puffball online and going into Patagonia to compare the two side by side, I returned the $55 puffball and shelled out the extra cash for the micro-puff vest. Since the micro-suff is on sale now, snatch it up.
My step-dad got the web special Das Parka, which appeared to have less loft than to one I got a year ago. I didn't do quite the analysis with the DAS as I did the vest.