Leica themselves marketed Schacht lenses in screw mount after they discontinued their own LTM lenses by early 60's. I own the 35mm F3.5 Travegon by Schacht in LTM and it is a very fine wide angle lens. So, if you are a Leica purist, these should be quite acceptable!
That said, there is no doubt in my mind that many of the aftermarket LTM lenses from the 1950's forward equal or exceed those of Leica, probably because of the very high bar set by Leica themselves. As an example, the Schneider Xenogon 35mm 2.8 LTM is an early aftermarket LTM standout, and German made too. There were many others (Nikon, Canon, etc.), unfortunately many of the early greats are uncommon today.