Unfortunately, if you go to many of the Amiga forum websites, you'll find a lot of negativity from a very loud minority aimed between these so-called camps. It's the remnants of the so-called "Red vs Blue" wars, where red represents AmigaOS 4 and blue represents MorphOS. For reasons unknown, a number of people still see fit to criticise and rubbish other camps every chance they get. Hopefully though, you can see past this and realise that most users are happy to enjoy their hobby regardless of the pointless bitching and bickering.
 

The classic category is somewhat complicated by modern re-implementations of the classic architecture in FPGA chips or similar hardware emulation. These aim to replicate the functionality and run the OS and software of the classic machines without the limitations of using 20 or 30 year old designs and increasingly hard-to-find parts. FPGAArcade is one such project that can emulate the Amiga hardware, as well as the hardware of other vintage computer systems, simply by installing the relevant core on the board.
 

Nowadays, OS 4 has received numerous updates and supports a small selection of PPC hardware, some based on industrial boards, others custom designed for OS 4, and classic Amiga hardware with PowerPC accelerators. Unfortunately this means that the price:performance ratio of these systems is quite a way behind mainstream hardware due to the high development costs and low production volumes. However, if you've used AmigaOS in the past, everything will be instantly recognisable if you sit in front of a computer running OS 4. Most old system-friendly software runs transparently on the OS while also benefitting from the extra speed of using native OS 4 APIs such as dos.library and graphics.library. Those programs that can't be run natively (usually programs that directly access the Amiga chipset, such as games) can be easily run in an emulation environment automatically. Workbench has been much improved though still behaves like it did in OS 3.9. There are a couple of extensions that improve the behaviour, such as Lister for Directory Opus style listers on the desktop. Modern features such as automatic updates of system components, 64-bit DOS, alpha transparency and compositing have all been added to OS4 through official updates over the years, and new hardware is in the works along with OS 4.2 which will supposedly bring multicore support to the OS for the first time.
 

MorphOS these days mostly runs on old PowerPC Mac hardware, which can be relatively easy and cheap to get hold of, depending on the 2nd hard market in your area. Having been written from scratch, some features are quite different from AmigaOS, however the API is based on OS 3.1 so most system-friendly classic Amiga software will run just fine. Instead of Workbench, MorphOS uses Ambient, a rethink of the Amiga desktop that feels more like a Linux file manager than Workbench, but with that offers more modern features such as opening drawers in the same window, iconifiable drawer windows and some other features, many of which require separate software to achieve on AmigaOS. The Amiga datatypes system has been reworked for MorphOS as well, and a new system called Reggae is provided as well that allows for streaming media amongst other modern features, making life easier for developers creating these sort of apps. Some areas are lacking however - ARexx is not included for example, though it can be copied over from a Workbench 3 installation. Similarly, some Workbench features are missing, such as caching the view all status of a drawer, using icon snapshot positions, and some are disabled by default such as dragging windows off screen and a program dock bar. So while it provides many new features, depending on your usage habits you may find the default ambient setup a little disappointing.

Being able to run MorphOS on many different Mac computers is a great advantage as it means you can install it on a laptop and bring it with you. I use MorphOS on a G4 iBook for my Amiga programming whenever I'm not at home. It is also possible to run it on the Sam460 board (an AmigaOS 4 board) and is planned for the upcoming high-end X5000 OS 4 computer, which allows users of both to run them on the same computer.
 

Unfortunately it's not quite as advanced as the other branches, and that shows on the desktop (called Wanderer). Fortunately however, the desktop replacement Directory Opus 5 is available for AROS (as well as for all other branches), which gives AROS a very powerful desktop indeed. Other shortcomings are not so obvious as they mainly concern the APIs and not the end user.

Several different distributions are available of AROS, each with its own bundled packages. The most popular is probably IcAROS, which is intended for installation on an x86 PC. It uses grub as its bootloader which will be familiar to anyone who uses Linux and can be dual-booted with other operating systems, though setting this up can be tricky.