Thank you for sharing your experience and your observations!
I had just a look at CMC and there the bitUSD rate looked quite close to $1, albeit with almost no volume.
And regarding Tether: customers would need to be KYC/AML compliant as well or would that only be necessary, if they want to cash out Tether for USD?
In the end your assessment seems to be valid: US-NBT is the best choice for synthetic USD at B&C Exchange at the moment.