Update
Having spent a fair bit more time with both the UP5 and the BTR5, there are a few more considered observations. To note, both units have been listened to with Fiio FH7's connected via a balanced 2.5 cable. To start with, I have found the LDAC connection to be sufficiently stable on the UP5 without any notable dropouts, at least with my S20+. Battery life on the UP5 has been sufficient and without issue, but admittedly, I recharge it daily. As such, I don't have any hard data on if the stated battery life is accurate or better than the BTR5.
As for sound quality, as of now, I'd definitely say that while using Bluetooth (LDAC), the UP5 is capable of pulling out a bit more detail from music compared to the BTR5, particularly in the low end. Also, there appears to be
slightly more weight to the sub-bass in the UP5 as well. To be clear, this increase in finer details (the plucking of double bass strings, see track below) was noted while using Bluetooth (LDAC) on both devices. That said, when connecting both the UP5 and the BTR5 via their USB-C connectors, any differences in sound quality between the two units became notably harder to distinguish. This makes sense to me as it is readily known that the sound qualities of the Fiio BTR5 definitely get a boost with a wired connection.
Overall, at week 2, I definitely feel that when using these two devices in the mode they were initially intended, via Bluetooth, the UP5 is currently coming out on top for me. As the sound quality of the UP5 is seemingly consistent no matter how you use the device, wired or wireless, single-ended or balanced, I think this gives it an edge over the BTR5. That said, the BTR5 remains an absolutely exceptional device. In fact, right now, the BTR5 presents a more polished product due to the length of time it's been in the marketplace. However, once Shanling releases its inevitable firmware (and app) updates, I feel this gap will quickly slam shut.
Indeed, the UP5 continues to impress. There are obviously still some features to enable (MQA), bugs to squash and app options to develop (Bluetooth or wired connection priority), but for now, well-done Shanling. Your move Fiio.
Comparison Track:
Roy Hargrove - Strasbourg / St. Denis (Track 3, Earfood 2008) [Jazz]