@TheMagicM
PortablE is a full-blown programming language, comparable to C++ or Java, and in many ways more powerful than AmigaE (although it does miss a few of AmigaE's more esoteric features).
The only thing that might restrict what you can do is that it currently only supports these AmigaOS modules: Asl, Commodities, Console, Devices (inc. Timer), Diskfont, Dos, Exec, Gadtools, Graphics, Icon, Intuition, Resources, Utility & Workbench, plus part of AmigaLib, class, Other & Tools.
Additional AmigaOS modules could be added if there is interest, but it is also quite feasible for
other people to add them too (since OS modules are little more than a text file listing what things an AmigaOS C header contains).
For more details, have a look at the manual:
http://cshandley.co.uk/portable/PortablE.html#2_2