Do my Montrails look so much different than my Adidas? Based on the results I just got by clicking Visual Search for a pair of Garmont trail runners, I would say this is useless for 99% of the items I purchase. I guess that's why I never heard of Like.com until today.
The one thing about Google shopping comparison as it stands, though, is it has a hell of time distinguishing between a "Canon 5D" and a "Canon 5D replacement battery". So "sort by price" is usually fairly useless.
If they can match the actual product pictures, which are commonly supplied by the manufacturer and thus, in fact, identical, that opens the possibility for meaningful multi-facted filter/sort. I can perhaps do a search that essentially ends up as filter:"Canon 5D" filter:"things for which the product picture looks like this picture" sort:"price, ascending".
That means that I can very quickly get better price comparisons.
On the other hand, what I would like to see more would be similarity search folded into the new Image Search. I would guess that this technology, especially if coupled with geotagging, would offer way better results for landscape photography than for running shoes. Even so, this is likely to help consumers and hurt merchants.
Which merchants? A photographer friend thinks the new Google Image Search will make it much harder to make a living selling photographs. If a visual similarity search is actually effective, it will pull the rug out of the fine art photography market. 1. Find awesome image from top pro commanding $1500 for a print 2. Do "similar image" search 3. Find similarly awesome image from some amateur wanting $250 for a print. 4. See top pros suddenly offering a lot more workshops and photo tours.