A port of Ambeint improves the whole of AROS and gives access to even more software in the long run, a port of Magellan just gives a a nicer desktop to those that want it in the short term.
Besides Magellan versus Ambient, the basic functions (file types...) are the same or at least similar. Ambient is (how I understand it) a configured environment (what is also possible with Magellan). The other difference is that it is based on MUI4, if that is a advantage or not is a matter of taste. Magellan has a lot of options for configuration too.
In fact Magellan has way more features and is more powerful than Ambient. Ambient has cloned some features from Magellan, but nowhere near everything and many times cut down solutions. Magellan is just older design visually (gui toolkit) than more modern Ambient (MUI4), but it still excels in feature wise. I'm still using Magellan for serious file management etc rather than Ambient on MorphOS.
