- Once I start using 7 and 8 sites simultaneously, having a very similar UI reduces mental load since I do not have to keep two ways of interacting in mind.
- I can evaluate how robust and power-user friendly Navbar actually is and if it is likely to need a lot of tweaks such as Admin menu was needed for Drupal 7 to work efficently.
Both modules are still rather beta and have their minor issues but overall it's a decent look-and-feel with what's possible in D7. The most annoying thing is not being able to create a node directly from the main menu, I have now actually started using shortcuts for this (which I previously just deactivated entirely).
So, as expected, it is a bit slower since the menu obviously relies on clicks but for me the responsive layout is already enough justification to relearn one or two muscle memories.
To use Devel you'll also need the sandbox Navbar Devel plus my patch for it makes it look decent. Environment Indicator also works right away with Navbar, so the only thing really missing from admin_menu is the fast user switching and command search but since I hardly use those, I don't have any major impediments currently.
I'm hoping some things like the floating settings block on the right might make it into Ember in the future but for now I have a good working alternative.
If you are in any way interested in Drupal 8 and are also maintaing any Drupal 7 sites, I highly recommend you check out "Drupal 8 Has All the Hotness, but So Can Drupal 7" as well as "Future-Proof your Drupal 7 site" for more ways to prepare for the future.