I realized there are many different thoughts on “the best firewall” and this is by far NOT a post about that topic 😊.  However if your organization uses ASAs and your looking to “Virtualize things(network) in the Cloud” the ASAv might be a great option for you.

For those who are not aware the ASAv is a Virtual Edition of the famous Cisco ASA (Adaptive Security Appliance).  The ASAv is based on the same software/code that is deployed on the physical appliances.
-Same CLI
-Same traffic flow (from a software standpoint)
-Same feature-set (+more, including ACI Integration, APIs, etc.)

The appliances can be deployed in Private, Public, Hybrid, VMware, KVM, Hyper-V, Amazon Web Services (AWS), Microsoft Azure and other cloud platforms.

I personally have used it in several deployments both Production and Lab for 2+ years now.  I would recommend it to anyone pursing a NGFW.