I think I'd rather they had used Gecko too, but Firefox wasn't anywhere
near what it is like to day back when they started working on Safari. I
think feature similarity is because both camps have been regularly
taking ideas from each other.
Firefox 1.0RC1 (aka 0.10.1) is rather nice. Works sweet on MacOS.
Something else I really really like about MacOS is the way you install apps. Generally you download a Gzip compressed .dmg (Disk Image) file. Which is automatically decompressed and mounted by the Finder/Safari. DMG's can be fully customized like any MacOS folder to have a background graphic, custom icons, etc. They also remember their "Finder" window size. So when they mount they come up as a customized window in finder. So they look just as good as any "InstallShield" wizard I've seen. Generally you then have a ReadMe (RTF) and an application icon. To install the app you just drag it from the mounted disk image to the "Applications" tab in Finder.
I realise this is very similar to the way MacOS has worked for ages. It is in stark contrast to the way Windows works and even the way Linux works. Though, I don't see why an RPM/DEB installer app couldn't be made just as simple (or simpler). Integrated into Nautilus and Konqurer etc.
Many things that MacOS does strike me as "the way computers should be".