I have owned the Yamato YF-19, sold it long time ago, and then got the YF-19 Double Nuts. In comparison to the Yamato VF-19S, the Double Nuts, feels rather cheap...like a KO. Now, after taking a close look at some photos of the Arcadia and Yamato versions, the Arcadia version would be a much bettter (visually as well as physically) choice. Plus, there's a substantial amount of accessories the Arcadia version comes with.
The Yamato Double Nuts is quite gapy in a few areas, which is a big disappointment, considering how much I paid for it. You can even get a Yamato VF-19S (which is much more solid, and heavier) for much less on ebay.
I'll probably keep the Double Nuts as I won't be transforming him anytime soon, and I do like the light grey and dark blue paint scheme.