My vote goes for 1/60. Yamato toys need some standard, instead of being scattered all over the place. 1/48 is nice, but too much of a novelty and far too impractical for other mecha like the Destroids and Zentraedi. OTOH, 1/100 is too small for Destroids and VF-1 Valkyries. The 1/60 scale is a nice compromise of the two extremes, in detail and more importantly: price.
I personally think 1/100 is another scale we don't need to deal with, but I don't care since I'm 99.9% certain Yamato will release a larger scale VF-0. What that scale will be, I don't know and I don't care, just as long as it's not 1/100. For now, I'll pass, my money deserves better than 1/100.