Here is Palm Beach County, I have tasted fresh picked Hak Ips, Sweet Hearts and Mauritius. Though for the most part the season has been just short of a bust, production wise, the quality of what I have tasted have been outstanding. While I really don't have to tout my favorite, the Hak Ip, these have been spectacular as have been the Sweethearts (yes, there are the two schools of thought with respect to the Hak Ip and Sweetheart: one in the same or two distinct varieties). I rest on the side that they are one on the same, and from what I have seen and eaten this season supports that. The size, shape, look and taste have been identical. The one standout has been the Mauritius. This years crop from Excalibur have been some of the best, if not the best, Mauritius I have ever tasted. While I have plenty currently sitting in my fridge of both Sweethearts and Mauritius (yes, the Hak Ips have all been devoured...hoping on a few sources for another batch in the near future), I am looking forward to what any other available varieties have to bring before the season ends here on the East Coast of SFla.
As far as the lychee nut, that is a definition termed to a dried lychee. Before the lychee was widely available commercially from the likes of Florida, China and Mexico, the main source available to the rest of the world was a lychee in its dried form, which was coined a "lychee nut".