Sails.js development has basically stagnated in the past year, and many people in the community believe Balderdash, the company behind it, aren't giving it the attention it deserves (they have a few new projects they're working on). Travis Webb and his team behind Trails were kicked out of Balderdash (not clear if fired from the company or just removed from GitHub group), and Travis blames Mike from Balderdash for doing it as a political move to keep control. Mike has said very little publicly about it, apparently not wanting to stir up more drama.
Trails seems to be an attempt at achieving what Sails has achieved (a full-stack modern MVC framework in node) with newer tools (ES6, I think Koa by default instead of Express, etc) and perhaps more modularity.
I think it's an ambitious project with good goals, but it will be a while before it will be stable and ready to use. And if it does reach that point, it's still susceptible to what's hurting Sails right now (a larger community than your developers can handle, de-prioritization, politics...).
Hopefully this turns out like the node / io.js split and is, in the end, positive for the ecosystem in some way.