In general, I think it’s useful to keep this basic rule of thumb in mind: Charles is relentless about absorbing good ideas no matter where they emerge; so, no matter what any other blockchain project is doing, the team will analyze it rigorously, and if it works, it will be added to Cardano’s roadmap.
In fact, the team is already integrating Directed Acyclic Graphs (DAGs) into Cardano’s roadmap to maximize scalability. DAGs are the primary thing that projects like Hashgraph and IOTA have that Cardano doesn’t currently have, but those other projects don’t come even close to Cardano with respect to optimizing the balance between security, scalability, interoperability, decentralization, and sustainability. Cardano’s capacity to optimize all these factors is what makes Cardano the ideal platform upon which most real-world applications will be built.
Projects like Railblocks and Radix (and all the others that claim incredible speed boosts) are making trade-offs between security, degree of centralization, and network cost, among others. In particular, they suffer from too much centralization for my taste.
However, I don’t consider myself an expert on their projects; so, I’m not sure if they have any realistic path to true decentralization in the future. But that’s why I say to keep the rule of thumb in mind: No matter what the latest faddish project claims to do, if it’s truly an innovation worth building, then it’s an innovation that will eventually land on the Cardano roadmap.