I don't remember seeing recent comparsions anywhere, and it's hard to avoid going a bit into which has done something better than other, but I'll try to write some points that pop up in my mind. This won't be a comprehensive comparison, but at least bring up some points which others can learn, fill, or use in their own comparisons
Starting from the points you brought up...
How can you tell which programs use Reggae, to make a conclusion that it wouldn't be used? MorphOS itself uses it quite much with its internal stuff and with the bundled software (MultiView, Jukebox, SCANdal, Jalapeno, and Flacapella pop in my mind, but probably almost everything in the MorphOS distribution uses it when handling graphics/sound). And compared to Datatypes, Reggae can also save files, which is a step forward. There are, for example, 3rd party internet radio players using Reggae, which can even save streams while listening them, thanks to Reggae. SCANdal uses Reggae to save scanned images to different formats etc. Reggae also supports streaming from the HTTP/HTTPS sources etc. So, this is a nice improvement over the old Datatypes system on MorphOS.
Graphics subsystems are basically quite similar on both MorphOS and OS4, at least from users' point of view. Both offer 32bit modes with 3D accelerated layers implementation ("Enhanced mode" vs. "Compositing"), which eliminates the old AmigaOS problem with stacked windows slowing down and also enables some transparency effects. There might be some speed differences etc, but can't remember any tests now.
OS4 supports newer graphics cards, but OTOH, there isn't that much point for MorphOS to go support latest cards, because most of the supported machines have non-replaceable graphics chips (Mac minis, IBooks, Powerbooks) or older bus where you can't connect newer cards anyway, and we also don't have software to take advantage of the latest cards on our PPC systems, so older cards do their job just fine still.
MUI on MorphOS is based on the original official code, and it's the most stable MUI implementation of all platforms. New features from the MorphOS MUI are then later converted to the unofficial MUI implementations on other platforms. Having a single officially supported GUI toolkit makes the user experience more consistent.
USB support and reliablility has been better from the start on MorphOS, thanks to Poseidon which didn't need to be written from the scratch, but of course there could be more active development regarding it. In any case USB on MorphOS got recently isochronous transfers support for USB audio etc improvements.
MorphOS also has support for FireWire in the kernel level, which lets you use FireWire mass storage devices and debug logging etc at the boot.
The
memory system on MorphOS is quite advanced and it's even possible to have different user selectable memory system implementations. The current default one is TLSF based, which reduces fragmentation, doesn't suffer from fragmentation, and is still highly compatible even with the oldest applications. AFAIK the memory system used in OS4 isn't quite this clever and is a bit slower, but OS4 has also memory paging support.
MorphOS Software Development Kit is constantly updated and offers the latest tools for developers. It includes updated GeekGadget environment, Git, OpenSSL/SSH, GCC 10 (and some older versions), GDB, profiling utilities,
Objective-C support with MUI framework, etc, etc. For comparison, OS4 SDK is more modest and hasn't been updated since 2015.
MorphOS also comes with a fully featured
Integrated Development Environment program. It also has more bundled/exclusive software (
Applications,
Utilities,
Tools) and you don't have to dig the net that much to get started, if at all.
The desktop software on MorphOS is more like Directory Opus Magellan alike, while OS4 relies to the classic OS3.9 style behaviour. MorphOS is more modern on this and offers more functionality. On MorphOS you can also browse into archives and image files without needing a separate filemanager.
Icon support on MorphOS has also moved forward quite much. It supports all Amiga icon formats, but also PNG (and dual-PNG which has two different images like on traditional Amiga icons) and SVG icons which can be scaled without loss in quality (btw. you can zoom icons freely too). Icons can also be "graphicless" where the icon image is taken from the deficons, but it isn't saved to the actual icon file. Each file can still have its own icon which contains tooltypes and other settings, but they're just very small ones because the graphics data isn't stored on them. These are extremely useful when creating new themes, because you don't have to replace thousands of icons for drawers and data files, but you just can replace few deficons. For example, a new graphicless icon for a drawer takes only 20 bytes, but you can still snapshot it and it fits correctly with themes on each user. You can also browse drawers in the Thumbnail mode, where icons are replaced with preview images of pictures and playing a small preview video of video files.
Screenbar modules on MorphOS are also lovely addition. You can populate empty area of the screen title bar with all kinds of modules to show informartion of provide functionality. These modules are visible on every screen then and you don't have to switch back to the Ambient screen to check clock, memory, cpu, or all that kind of information. This has been requested to OS4 by many users, but AFAIK there isn't equivalent yet.
Both operating systems have their preferred scripting language to replace the aged ARexx. MorphOS has Lua and OS4 has Python, and both implementations can communicate with old existing ARexx ports in programs.
Printing system on OS4 is quite similar to OS3 and would need some serious face-lift. On MorphOS you have native built-in TurboPrint for older printers and a whole
new PPD based printing system for newer printers. There's built-in support for network printing too.
OS4 has a built-in online updating software for OS components, although it's relatively quiet, but MorphOS relies just on bigger single releases. Both have 3rd party software for "packet managing" too.
Then there are lots of smaller but handy stuff which could be compared. Like RAWDISK: device on MorphOS, which allows you to copy image files of hard disks or partitions with standard copy commands. Better Amiga file attributes support with archiver commands (tar, lha, etc) on MorphOS... comparing all other new shell commands on both systems, 64bit support generally (network filesystems etc), etc... I don't know which level this should go
Well, phew... this came out of it. Might look like biased towards MorphOS, but that's the operating system I've chosen to use daily, so I guess it's more natural to see things from this angle. But hopefully this will help if someone wants to create a proper comparison table or something like that. And at least it should bring readers a bit more updated what's been happening on this side. Or course there would be a lot more room to go more detailed descriptions and I've probably forgotten to mention some fundamendal things too, but I guess this could be a start
