Exact Scan Pro (scanner utilities for Mac are still … all bad, this is absolutely good and relatively the best.
VueScan might be better for about 0.05% of all scans I do, but the usability could actually not be any worse)
Better Snap Tool (yah, don’t really get the split screen of OS X)
PDF Expert or
PDF Pen Pro (both good, the first is way cheaper, and the reason is that Preview can actually make PDF files bigger on edits like remove pages, or rearrange pages)