The Zen Blue V2 and the Rotel A11 Tribute are quite different when it comes to functionality. The Zen Blue is a Bluetooth receiver with a DAC and Rotel A11 Tribute is an integrated amplifier with BT capability and a DAC.
Having Ken Ishiwata on board even for a little while is a huge plus (RIP). Rotel A11 is a more rounded product - fit for many purposes.
The Zen Blue V2 is concentrated exclusively on BT connectivity. When it comes to Bluetooth signal reception
The Zen Blue V2 takes over Rotel by a mile. Rotel supports apt-X and AAC formats.
The Zen Blue V2 incorporates the newest Qualcomm QCC5100 chip in conjunction with the very latest version of Bluetooth – Bluetooth5.0. The QCC5100 is a DAC chip and could be used for the digital to analogue conversion BUT we use it for data processing only. It includes aptX and AAC codecs for best audio quality from Apple devices (AAC) and Android devices, laptops etc. (aptX). It will also enable our devices to process LDAC and HWA, Sony and Huawei’s answer to hi-res Bluetooth respectively as well as Qualcomm’s aptX Adaptive codec.
This means every possible source device is covered, at the highest resolution Bluetooth® specification. And future codecs can be added with Over the Air updates.
It all comes down to how would you like to use these two products. What do you mean by saying better sound quality? Are you looking for a DAC, an amp, a BT receiver or an all-in-one product?
Sound quality - I'll leave this one out, as it could be taken as too subjective.