How bad is it? Sylvester Stallone sings country music. That bad.
Should you see it? Yes, unless stereotypes bother you.
Sylvester Stallone's been in some intentionally campy films, like "Stop or My Mom Will Shoot" and some unintentionally campy ones like "Over the Top," but this one manages to be both. He plays a cab driver that is made, on a bet, into a country music singer by Dolly Parton. Sly's singing is slightly worse than his brother Frank's, in other words, passable, but his comedic skills are not good. Parton's fairly good, essentially playing herself, but the southern-fried cornball humor is scattershot (sorry about the mixed metaphor). Some of the laughs are intentional, some not, but there are laughs to be had.