I know I'll get flamed for saying it but I've used Aros, OS4 and MorphOS and of the 3, I have to say that Aros and MorphOS were superior in many ways compared to OS4. The comments about Aros requiring you to use outdated or second-hand hardware are total BS. Aros has some very narrow hardware requirements especially when it comes to wireless networks cards but I installed it on a Dell laptop with an nVidia GPU and have been very pleased with it. The only changes I had to make in terms of hardware was to replace the wireless card with an Aros-supported card. Aros also runs circles around OS4 and MorphOS just due to the fact that it takes advantage of modern x86-64 processors. If I had to rank the 3 OS's in terms of usability and performance, I'd rate Aros at the top, followed by MorphOS and lastly OS4.
