[goofballlogic]

As a UI architect I've worked on both SPAs and also ROCA-style UI quite a bit. Like everything pros and cons to both.

As a general rule of thumb I find SPAs deliver much faster, but ROCA-style solutions are much more predictable. That is, getting a modest MVP out the door with an SPA terms to be much faster, but almost always reach a critical mass of functionality at which point they become hard to maintain. ROCA-style apps don't suffer with this as much.

I don't think this experience is just down to the architecture however. I just think it asks a lot more of a software engineer to structure and maintain an SPA well. Ultimately an SPA can be a more optimal architecture for many applications because the client-side environment is an increasingly powerful VM in its own right. However, I rarely see the engineering discipline required to do it right.

I tend to prefer ROCA-style because it fits better with the web's distributed integration architecture, but in practice I find building an SPA with a resource-oriented mindset is usually a good compromise.