Cyber-Physical Systems require distributed architectures to support safety critical real-time control. Kopetz' Time-Triggered Architectures (TTA) have been proposed as both an architecture and a comprehensive paradigm for systems architecture, for such systems. To relax the strict requirements on synchronization imposed by TTA, Loosely Time-Triggered Architectures (LTTA) have been recently proposed. In LTTA, computation and communication units at all triggered by autonomous, non synchronized, clocks. Communication media act as shared memories between writers and readers and communication is non blocking. In this paper we pursue our previous work by providing a unified presentation of the two variants of LTTA (token- and time-based), with simplified analyses. We compare these two variants regarding performance and robustness and we provide ways to combine them.