The verdict
If your team has no developer and the process is contracts, forms and approvals, pick airSlate. If you have technical people, high volume or data that must stay on your own servers, pick n8n. I would not ask an operations team to run n8n themselves.
For general automation between apps, n8n is the stronger of the two. For a document that has to be signed and filed, airSlate has the parts built in, and in n8n you would assemble them yourself. If you want neither extreme, look at Make or Zapier.