Nowadays, some of the most successful models for global computers are defined as ambient-based calculi; among them, the mainstream models are Mobile, Safe and Boxed Ambients. In this paper, we comparatively analyze them and most of their variants by comparing every variant against the language it comes from. In particular, we discuss and compare: objective moves in Mobile Ambients; passwords and a different semantics for the out primitive in Safe Ambients; different communication and mobility primitives in Boxed Ambients. By establishing the possibility/impossibility of encoding one language in another one, we relate the three main models and, for each of their variant, we discover whether it enhances the original language or actually yields a different formalism.
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