Accessing your Mac filesystem from your iOS devices is great! Also quite handy if you need quick edits on e.g. your own webserver.
Really good integration with Files.app
I've been on the beta for ShellFish and I've seen it grow into an amazingly mature and robust product
Makes my iOS devices even more useful for development
None that I found
Using it as a beta tester since a couple of weeks.
Secure access to my files, from everywhere