Imo Long island restaurants are nothing memorable. I will say I used to like River Bay in Williston Park before they sold it. H20 in Smithtown is decent.
Zans Kosher deli in lake Grove is ok. If still there. Umbertos New Hyde Park is ok. Cuginis in Mineola has good solid pizza. Manhattan steak house in Cedarhurst was one of the best steaks around in Long island. Peter Luger Great neck was pretty good. Years ago when I went.
For me go to Queens or Manhattan for a better dining experience. Meet the meat in Astoria is great, Taverna Kyclades in Astoria for Greek fare, Akrotiri, Matiz Forest hills Spanish fare.