AmigaOS 4 comes in two variants. The first variant is the normal version, and is made for owners of the AmigaOne - which means three men and a cow can run this version. The other version is called AmigaOS 4 for classic machines, which means the Amiga 1200, 3000(T) or 4000(T) with a PowerPC accelerator board can run this version. This review is about the latter; the reviewer ran AmigaOS 4 on an A4000 with a CyberstormPPC 604e/060 233/50 MHz, a Voodoo4500 graphics card, an X-Surf network card, a Terratec512i-soundcard, and a SpiderII USB card.
The author likes the screen dragging features (which did not work on AmigaOS 3.9), its stability, speed, and the new look. He is fairly satisfied with the 68k emulation, which works at a reasonable speed. He misses a better shell and several applications ("Okay, there are a lot of things you can download from OS4Depot, but it would have been nice if the most useful things would have been preinstalled."). Some things flat-out do not work or work badly. There are graphical remnant issues, the network card driver crashes quite often, screenblanker fails, and the Grim Reaper appears too frequently.
The review can barely be called as such, but as I said, with such a small operating system you have to make do with what's handed to you.