The best think I like in Amazone RDS is it easy to scale the capacity without a reboot or downtime. So, it makes easy to power up your server when the number of concurrency user of your website increased. Moreover, the server running Amazone RDS is separate with your web server, so you don't worry about if the upgrade AWS RDS is affected to your web server.
Automatic backup, this is another excellent feature of Amazone RDS. It easy to setup & very useful for any web service.
Amazone RDS also integrate with Amazone CloudWatch, which help you to monitor your database, performance, throughput, etc.
Finally, the price of AWS is small with their features. If you are in free tiger, you total don't lose anything if you were using T2.micro instance
Amazone RDS is enough with almost of your requirements. But in some case, as my company, they want to backup the database in Amazone RDS into my company private storage. So, Amazone RDS Auto backup doesn't help anything for us in this case.
My company using Amazone RDS as our primary database in our web service. It does very well its job, and we never have to consider any problem about it. When something wrong in the application layer, it easy to restore the backup version of RDS and continue our work