All I am saying.
The RPi5 is the best RPi ever build. And it's IMO also the best platform for RPi based audio.
The entire PCie/USB/NVME/I2S environment was massively enhanced.
Meanwhile the OS/firmware/SW is getting rather stable, even though it's still work-in-progress.
What I am saying. I consider it a rather safe bet to go for a RPi5. Especially - and this is what this
thread is all about - if you own a Katana or audio HATs that makes use of the Allo driver. That
also applies to other Allo HAT interfaces.
I can't comment on the USB Bridge. I do mean to recall, the product was already outdated at launch.
A major shock and disaster for Allo during those days. Yep. Poor Allo. Allo didn't have that much luck
in its later days. Look at Hifiberry - they are still around - building their rather entry-level HW.
What they seem to have understood - keep focussing on your strong side - your niche!
All the other potential areas of improvement, such as
- audio interface types (USB/I2S/SPDIF)
- Wifi
- network storage (NAS/NFS)
- separate client/server setups (incl. UPNP, LMS/squeezelite etc.)
- storage media (SD/USB/NVME)
- internet streaming services
IMO can and in my experience do have an impact on your perceived SQ. But that applies to all RPi/computer audio
platforms - which would include commercial streamers as well. On that part you could stick to your existing platform and
try to work on these parts first.
Anyhow. Good luck with your choices. There's no right or wrong. Just a "slightly better or worse".
Bottom line. Let's keep going on that rather fuzzy mission towards .... - what was it again ???
Enjoy.