Interestingly enough, the NY TImes reviewed Tennessee Jack's in Sunday's (Nov. 20) Long Island section (I subscribe, so I got that section on Saturday). As of this writing, it's not available online.
The review seems to have echoed my experience, to the extent that it overlapped.
Atmosphere: Rustic roadhouse with Southern barbecue
Service: nice, helpful, not polished
They called the pulled-pork sandwich "a must." Sliced brisket, "fork-tender and bursting with flavor." Smoked half-chicken "fell from the bones." The marinated grilled salmon in a Carolina-style mustard-based barbecue sauce "put to shame" many the reviewer "had at more expensive restaurants." It's unclear what she was specifically comparing it to at those other restaurants... fish in general, or similarly prepared salmon?
Ribs: for three racks on two occasions, "two were succulent, flavor-packed and perfect but one rack was dry." That echoes my experience--the first order of ribs I had was unimpressive; on the return trip, they were very good. The only entrees I've had so far were the lunch-order ribs.
Mixed reviews on the sides: "skip the dry corn muffin." Also skip the mashed potato, baked potato, and corn on the cob. Kudos for the coleslaw, French fries, and baked beans. My experience was the same: utterly forgettable corn bread, tasty baked beans.
For those not familiar with the NY Times reviews, the rankings are: Extraordinary, Excellent, Very Good, Good, Satisfactory, Fair, Poor, based on a combination of the food, ambience, and service, and taking prices into consideration. Take that however you want; I prefer places where the waitstaff doesn't dress better than I do.