I have tested both apps and so far I prefer the performance and ease of use of RedLaser. While ShopSavvy does more than RedLaser, it shows that it is a port of an Android app and it does not feel like a real native iPhone app. For example, RedLaser product detail page fetches the very well done iPhone-optimized version of Amazon.com, while the same page on ShopSavvy opens the desktop version of Amazon.com, which is practically impossible to navigate.