I was impressed with Easy-ISLisp lately, an interpreter/compiler. It processed any ISLisp I threw at it, so seems complete. Although I like ISLisp I still think I'll stick with CL day-to-day, mainly because I'm wary of finding a local maximum for the programming language at a cost of libraries (QuickLisp is great) or OS integration/support (e.g. how do you do threads? The awesome-cl list will tell you.). If I was just searching for the best language I'd probably use Idris 2 :-)