Jechilt,
if your main concern is the ease of navigation, I am afraid that neither the VA 76 nor the SD 1 will satisfy you; the VA 76 requires some time to get accustomed to its logic and to the touch screen, which is not the fastest way to communicate with anything, and from what I have gathered the SD 1 too is not so intuitive or easy to grasp.
From this point of view (i.e. fiendly interface and OS) I think that Yamaha or Technics have more to offer.
What I can tell you is that, at least in my opinion, the VA 76 and the SD 1 have the best styles among all the arrangers and some of the best sounds too.
I am sure that other Forum members will give you their advice and you will be able to make an informed choice.
Good luck,
Andrea
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.