G4 MacMini's are excellent choices for running MorphOS3.1. The 1.5GHz models are better than all the other models, due to them having 64mb of VRAM, instead of only 32mb of VRAM, but even the models with 32mb of VRAM will work well enough to do MorphOS3.1 programming, or check any developers code to see if it will run okay on MorphOS3.1.

I was lucky enough to find a very good deal on several 1.5GHz G4 MacMini's last year, so that is what I bought and gave away to a couple of programmers who wanted to run MorphOS and check their code on, to make sure it works with the latest versions.