Nothing does as well in my dry/shady yard as longevity spinach and okinawa spinach in close second as they must be very closely related.
Of all the kinds I've tried though, new zealand spinach tasted best to me, though it has yet to grow very well. I'll keep trying it, sometimes it just takes a bit or experimenting with the conditions.
Bele I've been growing are a bit too tough of a texture for me, but maybe I've gotta get some better new growth or something.
Malabar seem to need more water than I have here.
I've got the sissoo/brazilian spinach going as well, and I had a leaf once that tasted great, but most of it since has been too tough and bitter, so maybe that one would be good in the right conditions/timing.
I love your title "best fake spinach," lol.