How do you decide which type of workload should be run on private and public clouds?

You can run any type of workload in the public cloud. At the end of day, the VM/Instances in Cloud are regular Linux or Windows machines. The Cloud actually gives you even more options/services to run your workload.

Does Aviatrix use Terraform to deploy/automate across the Cloud platforms?

Yes! Totally! For Terraform, we are an official provider. Also we support REST API.
https://www.terraform.io/docs/providers/aviatrix/.

What is the benefit of using different Public Clouds, why not consolidate on one preferred cloud?

You want to diversify. Just like how you would do main DC and DR in separate locations, it makes sense to be in different CSPs. Sometimes, there are better offerings in terms of services and support and cost when it comes to different CSPs.

Are the controllers and the gateways multi-tenant? 

Yes. The Controller allows you to onboard different accounts from different tenants. Then you can build the environment as isolated as you like.    

Can the controller live in two different cloud providers?

The Controller is a SINGLE instance that lives in a single cloud. However, you can restore it in any cloud you want for DR.

When building a tunnel between multi-clouds (ex. AWS to Azure), is this being built through multiple transports?

The usual method provided by CSPs is the Internet, and that’s what we use for multi-cloud connectivity. For inter-region we can use the native cloud providers' backbone.

Is there any functional difference in Aviatrix, based on the CSP it is hosted with?

Not really. The Controller’s software is the same. There may be a small difference when setting up HA, though. For example, in AWS, you set up an Auto Scaling group but in Azure or GCP, it’d be different.

What is the max bandwidth between Aviatrix Gateways?

This depends on instance sizes you choose and what cloud provider provides. For example, in AWS we can do 75 - 80 Gbps.

To get 70Gbps of encrypted traffic from Aviatrix gateway to the Client Tenant, does the client need to spin up multiple VPN gateways? Can the traffic be encrypted over the ExpressRoute?

You can't get 70 Gbps to the on-prem. The ExpressRoute is at max, 10 Gbps per connection. With Aviatrix, you can encrypt that to get 9.6 Gbps over ExpressRoute.

Can you auto scale the Aviatrix Transit Gateways?

Gateways can be scaled up directly from the Controller. You would pick the size based on throughput requirement: https://docs.aviatrix.com/HowTos/gateway.html#select-gateway-size. It is hitless resizing. We looked into auto-scale options, but the majority of enterprises do not want it to happen automatically. 

Does Aviatrix controller offer a cloning option to replicate a deployment that exists on Azure, for example, to another deployment on AWS without having to do it manually again?

This can be very easily achieved with Terraform modules for Aviatrix.

Between which end points is the IPsec tunnel built?

It is built between the Cloud and On-Prem router.