For the record, everybody except Douglas Self calls this a single stage design.
Distortion is only speced above 100kHz, but the slopes are increasing so it should be better below 100kHz.
This seems related to AD797, which has the same voltage noise except near 20Hz, and has been tested by Samuel Groner to be one of the lowest distortion opamps out there. In particular, it is essentially unaffected by 600Ω loading and apparently drives 200Ω better than TI's OPA211 (industrial version of OPA1611) drives 600Ω.