What's great
Having used other automation tools like Mindpal, I can say that anytime I can automate a workflow with Relay, I will. It's intuitive, the support is outstanding, the features keep getting better and better, and the AI assistant is actually very good. The integrations are great - the things Relay can do with LinkedIn I have not seen anywhere else (and I've tried.). The only reason I use anything other than Relay is when I need external facing automations. The founder, Jacob, is fantastic, and so helpful with terrific training. I can't say enough good things about Relay.
What needs improvement
One edge Mindpal has is the way it can present external links and embeds for workflow you need to share with people outside of your organization.
vs Alternatives
Make
MindPal 
LindyYou can go from zero to productive with Relay. It's more intuitive and the AI assistant is really good - much better than Make's. The LinkedIn integration is the best out there. All the integrations I need are available. It's the best.
Which critical apps integrate natively beyond Gmail, Notion, HubSpot?
A lot of them do by my experience is with LinkedIn, Gmail, Notion, Fathom, Slack, Open AI, Anthropic.
How well does human-in-the-loop approval work in practice?
Excellent. I use that feature for content writing.