as a matter of fact, our app is using multi-zones not just for instances but also for RDS. As of now, I can't reach anything including the loadbalancer.
All I've ever heard and seen in practice is that RDS should generally be avoided for production usage. Its opaque reliance on EBS is its downfall.
Possibly but there are bigger companies using RDS in production – also, the multi-az feature had worked out better than my own custom setup. Unfortunately lack of resources prevent me from rolling out my own setup on bare metal.