Fusion 360 vs. Onshape, Round 1

Advantage: Autodesk Fusion 360
UI Responsiveness: As an application executing locally, it is vastly more responsive to my actions than Onshape executing across the internet.
Integrated Assembly: In Onshape, parts are created in Parts Studios tabs and put together in a separate Assembly tabs. Parts need to have designated "mate connector" added to their designs before the assembly can occur. I never got the hang of this system. In contrast, every Design window in Fusion 360 can import parts from other designs without special entities like mate connectors.
Advantage: Onshape
Constraints: Onshape is really good about informing the user of constraints. Sketch entities are blue when they are under-constrained. When they are properly constrained, they turn black. When they are over-constrained, the conflicting constraints are all highlighted in red.
In contrast, Fusion 360 makes no distinction between under and properly constrained. My only indication an entity was under-constrained is long after the fact, when it would move unexpectedly in response to a change elsewhere. When over-constrained, a dialog box tells you the latest action causes over-constraining, but it doesn't show you the conflicts so you'd have to go hunting for conflicting constraints yourself. This is a lot of lost time and a huge drain on productivity.
After a week of Fusion 360, this is the Onshape feature I miss the most.
UI scaling: Browser makers have lots of practice dealing with variable sized content on variable sized screens. Running Onshape in a browser window at 4K resolution was painless. In contrast, Fusion 360 scales poorly on a 4K screen, leaving many UI elements tiny and difficult to use.
Other Notes:
Sharing: Onshape free tier users are not allowed private documents, so every file is automatically shared with the world. Fusion 360 was designed for a world with designers and customers and clients, so it has a bunch of tools to manage access and permissions. In all that complication, they seemed to have forgotten to include a simple "share with the whole world" option.
Updates: Both of them update frequently. While it is easier to pick up an update in Onshape (refresh the browser) the Fusion 360 auto-update has been fairly seamless so far.