We (3 couples) were visiting Key West the 1st week of June, 2013, during a spell of unusually wet & cloudy weather, but Grunts had been recommended to us so we ate their between the raindrops. The reason the weather is critical is that, with the exception of a small building with a bar, all of the action is outside. However, it's worth the gamble, and, in nice weather, this gem might have gotten 5 stars from me.
Our host, a great guy from the Czech Republic named Milan, slid two round tables as close together as he could to accommodate our party of six, and we proceeded to enjoy a great meal under big umbrellas (it wasn't raining, but it sure was threatening to). Most of my party tried to lobster mac & cheese appetizer, and all raved about it. I tried the conch ceviche, which was very tasty although a little chewy.
I don't recall specifically what we had as entrees, other than one person enjoying a burger and one eating the excellent fish tacos as a dinner. I do remember that all of the dishes were excellently prepared, with the exception of one overcooked hamburger, but that problem was immediately remedied and Milan even left the original burger in case someone wanted it, gratis.
What made the place special, besides the wonderful food, was Milan. After a discussion about every restaurant we tried claiming their Key Lime Pie was the best anywhere, we told him that we were too full for dessert this particular night. He tried to convince us that we had to accept his challenge, but to no avail. While we were enjoying our coffee, Milan reappeared with two slices of the pie, insisting that we at least try it, on the house. That, to me, was an above-and-beyond gesture which meant it wasn't just for the profit that he was trying to get us to sample it for dessert. It was excellent, by the way, although there was one I liked better (Chef Michaels in islamorada). I would give the pie an easy 4 stars though.
We enjoyed our experience at Grunts, despite the weather, but within an hour of our dinner it poured really hard, so I don't know how we would have fared if that had happened while we were eating. That being said, I would highly recommend you try Grunts on a nice evening in Key West.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.