I saw the machine and glanced at the shelf when I was there last year. The books on display are a very mixed and odd bag - novels, local histories, poetry, and I think I recall a cookbook as well. Some were professionally done; others were less so, to put it charitably. It's tucked in a corner next to either the SFF or mystery shelves, IIRC. If you have a fan base and can promote the book enough locally to drive people there to specifically ask/look for it, then it might be a good deal. But generally, I don't think people go in there to browse the Opus shelf - precisely because it's such a mixed assortment.
Just two bits from someone who's only been there once!