Whether our clients are VPS hosting providers or operate private cloud infrastructure for their internal enterprise requirements, CloudStack provides solutions in an easy to implement and operate way that is simple to provide training for. The learning curve for our customesr adopting CloudStack for the management of their cloud infrastructure is shallow, enabling our clients to come up to speed quickly without having to outsource their administrative functions any longer than necessary
Where you already have some Chef recipes to build your application boxes and are happy to run directly on VMs, OpsWorks really shines. It won't do anything too complex for you, so it only really works well for simple stacks (load balancers, application layers, database layers). If you want to do more complex infrastructure, Cloudformation or Terraform are probably worth looking at.
Getting up and running with OpsWorks is a very technical and potentially time-consuming process. You need to know the ins and outs of Chef/Puppet if you really want to get into it and there isn't a convenient way to test out the environment locally so debugging can be time-consuming.
To take advantage of some of the newer AWS instance types you need to be running on a VPC, which again is a pain if you don't have a DevOps team.
The error logs and monitoring metrics in OpsWorks are pretty basic and haven't changed much over the years.
Unless you pay for a pricey support package getting support on OpsWorks will be pretty slow. Documentation is also relatively limited and sometimes hard to follow when compared to competitors. Generally, we've been able to get the answers we need from OpsWorks support when we run into problems but don't expect rapid responses.
The University, my first large implementation, had a big issue with 149 small data centers spread on São Paulo State, this data centers costs to university were very high, the consolidation idea in two data centers were awesome, but were worried with the management, so we adopted ACS to management of all 576 physical hosts. Now a days the university is delivering IaaS for all staff, students, teachers and researchers, they are using these resources to delivery services to their clients and have a great results in research area
OpsWorks isn't really a direct competitor to Terraform/Cloudformation, but it does allow you to do some of the more simple things on offer quite quickly and effectively. Opsworks was used for this reason, along with existing internal knowledge of Chef. Along with some of the other services on offer from AWS, it is good to use as a stepping stone along the way when building your systems - or perhaps it would be entirely suitable for a fairly simple project.
