During the development of Critical Embedded Systems (CES), quality attributes that are critical for them (e.g., correctness, security, etc.) must be guaranteed. However, this often leads to complex quality trade-offs, since non-critical qualities (e.g., reusability, understandability, etc.) may be compromised. In this study, we aim at empirically investigating the existence of quality trade-offs, on the implemented architecture, among versions of open source CESs, and compare them with those of systems from other application domains. The results of the study suggest that in CES, non-critical quality attributes are usually compromised in favor of critical quality attributes. On the contrary, we have not observed compromises of critical qualities in favor of non-critical ones in either CES or other application domains. Furthermore, quality trade-offs are more frequent among critical quality attributes, compared to trade-offs among non-critical quality attributes. Our study has implications for both practitioners when making trade-offs in practice, as well as researchers that investigate quality trade-offs.