What are some alternatives?
When comparing Collabio and PDF Expert, you can also consider the following products
Google Drive - Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
FileZilla - FileZilla is an FTP, or file transfer protocol, client. It lets individuals transfer single files or batches to a web server. For many years, FTP was the standard for website design. Read more about FileZilla.
Microsoft Office - From desktop to web for Macs and PCs, Office delivers the tools to get work done. View product information or sign in to Office 365.
Beyond Compare - Beyond Compare allows you to compare files and folders.
WPS Office - Would you need Office Word, Excel or PowerPoint for Home, business or School? WPS.com would give you right version for you.
PuTTY - Popular free terminal application. Mostly used as an SSH client.