I read somewhere...think it was on dslreports or something about poor netflix performance and people said it was because netflix was trying to get comcast to go with a plan that allowed netflix to host servers on Comcast infrastructure for free to provide better service to comcast customers. Comcast said no way because it is your responsibility, not theirs, to provide the required bandwidth at peering points from your partners. Then netflix looked to net neutrality, hoping to force ISPs to open up the bandwidth no matter the usage. Then on Feb 24 Netflix and Comcast signed a deal where netflix pays comcast and is allowed to use comcast's network directly to serve movie streams. They dropped Cogent which was a middleman as the primary route into comcast's networks, but cogent was unable to keep up with the demand which prompted netflix to try to work out deals with ISPs. It seems that now they are going to start paying for access to the major providers' network.
What this means is that if comcast was throttling before which I heard they did but never really experienced, they will no longer, as netflix is doing direct peering to comcast now and paying a fee for this access which basically tosses the net neutrality thing out the window. Other ISPs may do the same thing. Allow Netflix direct peering if they pay them, otherwise they will continue as they do now...if it works great, if it doesn't you blame netflix for not paying for enough bandwidth through their peering partner.
Anyhow there is no reason Netflix shouldn't be getting SuperHD through the XB1. I mean it even works through my Blu-Ray player and TV which both have super slow processors and much slower network features.