What's great
Swell's subscription platform out of the box is the best I've seen. It does everything. No plugins, no 3rd party apps, just a thoughtful native platform you can use immediately.
Everything is intuitive, support is exceptional. And you can customize to your heart's desire. For example we built our own customer portal and added tons of cool features for our members.
If you're in e-commerce... you'll be hard pressed to find a better platform, especially if you want to run any subscription based products.
vs Alternatives
Their subscription platform is second to none.
Are the no-code integrations reliable and well maintained?
The integrations they currently have worked with zero issues. For example: Shipstation and Sendgrid, I've used personally and it was seamleess.
They just rolled out their new storefronts as well and I am sure they will continue to innovate and get better. That's been my experience.