Assuming storage is not a problem, you might want to consider the ML 120 as it is an upright machine (like the Neos) as opposed to the 100. Believe me, you will prefer an upright to a table top stringing machine. Then, the prices are about the same.
I am a Neos guy personally (disclaimer) and if I were buying a new machine I would probably buy another Neos. But I would look at the Gammas suggested above before makeing a final decision. What I like about the Neos is the convenience, the speed (I don't think you will find a faster machine) and the durability. Check out other threads and I think you will find a consensus that it is built like a tank. The two point mounting is efficient and effective. I have not used the ML 100 or 120 but both are drop weight and constant pull--the Neos is a lock out. I think the difference is ultimately a matter of personal preference--any practical differences between the two mechanisms are sometimes overstated and in all events can be compensated. Keep any machine you purchase clean and properly calibrated and you will be fine. Good luck.