I don't know much about the internals of Chromium, but I'd say it's more than a "low effort reskin". Not including the UI changes like vertical tabs and collect

I don't know much about the internals of Chromium, but I'd say it's more than a "low effort reskin". Not including the UI changes like vertical tabs and collections, there's also a lot of underlying changes/improvements made like PlayReady support (for e.g. 4K Netflix playback), better scrolling support, tracking protection, Windows-specific improvements, memory/performance improvements, PDF annotation, web capture, etc. Granted, Microsoft are contributing most of these underlying improvements back upstream to the Chromium project, so the gap between them will remain small. Second to Google, Microsoft is the most prolific contributor to the Chromium project, so I think "low effort reskin" is a bit of an undermining to their efforts. With all of that said, Google is still the gatekeeper, Microsoft's contributions don't really solve the Chromium browser monopoly, and Microsoft is being really scummy with their push for Edge (i.e. Windows and Bing annoyances about it). I'd still prefer to have more independent browser options like Firefox.