Far as I'm concerned, all the LTM lenses l've had are delightful—from ancient ones that I had in yesteryear to the relatively new Voigtländer Color-Skopar 28 and 50 mm lenses I still own. I don't really see much point to reading reviews about them ... some are better on test charts than others, but why really care about that? What's fabulous about these lenses isn't how well they shoot test charts but how their qualities in making real photographs enhances what you're doing.
Voigtländer made a few fast Noktons in LTM ... I had the 50/1.5 and the 40/1.4 and both were very nice performers.
My favorite of the modern LTM lenses is a toss up between the Voigtländer 28/3.5 and 50/2.5 ... Not super fast, but compact, beautiful rendering, lovely size and weight. I use them today, occasionally, with M-bayonet mount adapter on my Leica CL where they give me that nice combination of wide-normal and short-portrait-tele FoVs, or on my M4-2.
G