Honest comparisons between PDFShore and the most-used PDF tools online. We say what they do well and where we're different. The short version: they upload your file, we don't.
iLovePDF is fast and polished, but every file you touch goes to their servers. PDFShore does compress, merge, and split in the browser. Here's an honest comparison.
Smallpdf has a beautiful UI and great mobile apps, but the file always rides up to their servers. PDFShore runs the same compress, merge, and split locally.
Adobe owns the PDF spec and their online tools handle the edge cases. They also need an Adobe account for most actions. PDFShore covers the common jobs locally and for free.