I own the QB-9 DSD and have listened to the Metrum Pavane. If the Hex sounds close to the Pavane, then I didn’t really hear anything that made me want to part with the Ayre. However, the Hex is more flexible with regards to digital inputs.
One thing to note, I believe the DSD update to the QB-9 included, among other things, an update to the USB receiver section to make it self-powered rather than draw current from the bus. Might be something to consider if you feel it of benefit.