I'd never heard of Showmars before I moved to Charlotte, so it must be a semi-regional phenomenon. I've always heard good things, though, so I decided to check it out recently.
The reviews were right: this place is pretty good. You're not getting all that much in terms of ambiance: it's formulaic and kinda cheesy inside; it's what you'd find at Applebee's or Chili's, which makes sense since this is a semi-chain.
However, Showmar's menu is extremely extensive. You can literally get whatever you're craving here, and I do mean anything, from burgers to pasta. And it's all pretty affordable--really affordable, actually. Good for a quick lunch or quick dinner, on the cheap.