Service mesh is a powerful pattern for implementing strong zero-trust networking practices, introducing better network observability, and allowing for more fine-grained traffic control. Up until now, the sidecar pattern was used to implement service-mesh capability but as the technology matures, a new pattern has emerged: sidecarless service mesh. Two prominent open-source networking projects, Cilium and Istio, have implemented a sidecar-free approach to service mesh but they both make interesting design decisions and tradeoffs. In this talk we review the architecture of both, focusing on the pros and cons of implementations such as mutual authentication, ingress, and observability.