Congrats on the DirectStream arrival! I found that the DS sounded good out of the box and gradually better for the first 600 hours or so and really was different (in a great way) 600 hours plus than when new. With the new firmware Huron, and a lot of seasoning, the DS is giving me sound I am so so happy with.
My experience with the ZBit and my DS and Torii Mk III (along with more input from Randy et al) can be found in this thread:
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1429468397/47#47 I don't have any experience with the ZMA to add.
I'm very happy with the ZBit, though I was also very happy without it and I could cope without it, but am glad to have it. I'm going to take it out again this week and try putting one of my CSP2+ back in, as I'm beginning to see how that might be a benefit as well, in its different way than the ZBit, and the CSP2+ will allow me to send the output of the DS to both my Torii and my Taboo headphone amp, which would be a boon. But I won't be parting with the ZBit even if I end up keeping the CSP2+ paired with the DS, the ZBit will be helping out my second system. It's a fantastic product and I'm very impressed with the solution that Steve came up with for balanced to single-ended output.
I'd be interested in hearing your impressions about the broken in DS in comparison to the Zen DSD when that time comes. . . .!