Comment Re:pdf.js (Score 2) 132
Office Automation is problematic -- because it literally opens up a hidden window of your Office app and simulates clicking around the UI to do what you need, if something unexpected happens it can unhide the window to show the user a message. This might be good enough for a desktop app, but if you're running it on a server it'll just freeze up your process with noone there to click it.
For Office->PDF conversion of word docs, Aspose.Words has a fairly easy API and generally very accurate rendering. I highly recommend it.