Many times, 2-page magazine photos "don't match" and part of the image is "lost" where the right and left pages are joined in manufacturing. I tried matching with DoubleTake and was able to "fake" the small (1/4 inch) blank between the right and left pages (with Clone Tool in PhotoShop) so that the image looked complete and fully aligned.

PhotoShop Merge can't do this< at least not as well or as quickly>, so I'd say DoubleTake is worth it as an extra photo-stitching tool.