Start with who will maintain it
The best platform is the one the person who owns the workflow can read and change. If your team will edit it, favour the tool they find least intimidating. If an engineer will own it, the calculus changes.
A workflow nobody understands is a liability the day its builder leaves, whatever it runs on.
Check how each one bills
The three bill on different units: Zapier by task, Make by operation, n8n by workflow execution on its hosted plan, or not at all if you host it yourself. A workflow that loops over hundreds of rows behaves very differently under each model.
Price a realistic month of volume, not a single run, and check each vendor's current pricing page before you decide. Plans change.
Look at where the data is allowed to go
If documents are confidential, where the workflow runs matters. A self-hosted n8n keeps execution inside your own infrastructure. Hosted tools process data on the vendor's servers, which may or may not be acceptable for your contracts.
Count the branches and the error paths
Simple linear flows are comfortable anywhere. Heavy branching, retries, custom code and long-running steps are where the tools differ most. If a flow needs real error handling, test that first, not last.
When none of them is the answer
Some jobs outgrow any visual builder: high volume, strict latency, complex permissions. Those are better as code. The point of starting in a visual tool is to learn the process cheaply, and to move to code only where the evidence says to.
Related