As I posted that I took on certification challenge and I have passed my first exam, I also passed the second exam (AZ-301) and I'm now a Microsoft Certified: Azure Solutions Architect Expert!
Exams are particularly difficult for someone with a developer background. Even though I'm more focused on PaaS and SaaS components these days (like most people), the exams mostly cover IaaS components such as VNETs and VMs, including the disaster recovery scenarios with Azure Site Recovery. They also include a lot of Hybrid-Cloud scenarios, again with Azure Site Recovery. Long story short, most questions come from Azure Site Recovery (sigh). I understand the point; as an architect, you need to be confident around network and security components, but I believe it covers a tad too much of the exams.
Another area that exam heavily tests you is Azure Active Directory and its synchronisation scenarios. Especially with Azure AD Connect and how to use it with Hybrid-Cloud requirements, such as multi-national corporations with multiple regions as well as multiple on-premise sites. Again, as a developer, we mostly focus on how to use AD rather than design it, so it requires a bit of first-hand knowledge there.
However, it is manageable and achievable, and I'm happy to prove to myself that I'm capable of covering those scenarios, which mostly was in my blind spots. I hope to encounter many more different use cases!