Since both are available for download, I'd just pick the one you'd need a user-manual for. They both support extensions to the core language so you'd better learn how to add them as well.
If you see a copy of AmosPro with a manual you'll be in fine shape. I wouldn't go for the watered down versions of Amos the Creator or Easy Amos but I'd insist on getting the pro version. When writing programs, be sure to download a copy of the AMCAF extension since it seems to be the most useful one.
AmiBlitz is the modern BlitzBasic with bugfixes and new features. It will compile well for 68k processors but the current maintainers aren't planning on a version for newer systems.
A project I'm working on is called Mattathias because, like its namesake the son of the prophet Amos, it is designed as a sequel to Amos. However, in order to keep things flexible we might be able to add support for other parsers as well. Since Blitz is still maintained, adding a parser for it would be a moving target and the Amos compatibility extension is planned to be first.
Be sure to post back here with the one you choose to download or buy.
