Apple released the second public beta of iOS yesterday, I've got it running on an iPad Air 2 and it fixes a couple of the annoyances I had from the first beta but adds a few new "learning opportunities" for the developers.
I've already written about my initial views on the iOS 11 user experience. One of my gripes, having to tap-hold an app to kill it from the Control Centre has been fixed. Now, when you open the Control Centre, you can swipe an app upwards to kill it.
The Dock continues to be a bit of a mess. While I learned it can be customised with more icons I find the apps it places in the area set aside (but that can be disabled) for recently used apps is a crap shoot as it what will be there.
Using the iPad Air 2 with an external keyboard (it's what I'm using now) works well but using the Cmd-Tab keyboard shortcut for switching between apps is broken. Aside from still being a bit laggy - not surprising in a beta build - it doesn't always show the most recent apps.
On the upside, the Cmd-C and Cmd-V keyboard shortcuts seem to work more reliably now.
The Files apps now supports Dropbox (I couldn't get that working with the first beta) as well as fileshares on macOS Server. But the third-party integration is still poor in my view. When you open Dropbox or OneDrive, they appear as a pop-up rather than integrated into the main screen like Apple's iCloud Drive. I expect (hope) that will be resolved through updates issued by software makers.
I haven't installed the beta to my iPhone yet - it's a primary device and my only phone so I won't be messing with it.
If you want to take a punt on running the iOS 11 public beta, you can follow these instructions on accessing it.