I did two of these, one for two years, one for one year, both elite places. And then I landed my current t-t position (in addition to being competitive for other t-t SLACs). The teaching experience I got in these positions was invaluable to landing my current job. I was able to publish, as well. I learned how SLACs operate. There was no service required, and any small amount I did was appreciated like crazy. I got a great letter of rec out of my first position (although that's not too feasible in a one-year gig). And, honestly, it was a cushy existence.
I've recommended these positions over postdocs to anyone who wants to be at a more teaching-focused school. The biggest pain is not being able to set down roots and having to cancel class for job interviews, but that's not much different than a postdoc.
Appealing things about me, I think, were:
- some prior teaching experience, particularly an ability to teach the necessary classes but also to offer something new
- being willing and able to mentor senior thesis projects (as most/all of these students have to do a thesis and supervising them is a lot of work)
- research that could easily translate to that environment
- something exciting and novel to students. If you give a job talk, it's important that the students are psyched up by you. They are cherished in these schools.