For me the Quectel firmware was very stable whereas the OSS firmware wasn't. "Stable" as in it would periodically crash, but would come back on its own within a minute. The OSS firmware would also crash but would usually not come back until a reboot.
This was with v0.5.5 IIRC. It seems to have gotten better since the 0.6.x versions of the OSS firmware.
Really the bigger reason to switch to the OSS firmware is that there's a privilege escalation vulnerability in the Quectel firmware that IIRC they still haven't fixed. In any case even if they fixed it in a new firmware release you wouldn't hear about it to know you should install it, whereas the OSS firmware is now being distributed through fwupd so it could be almost as mindless as updating your distro.
Maybe you could share if you tried it with the normal PinePhone or the PinePhone Pro as well.
> "Did the modem randomly die without you doing anything" Yep
> "Or under high load it gave out sometimes?" No, it would be just idling/sleeping and it would crash on me. It's not like it would automatically restart itself either. It was just dead until I rebooted the phone (which is slooowwww), restarting the modem manager and the modem it self, didn't fix it reliably for me either, only sometimes that would actually work, that whole process of restarting the modem and reentering your PIN could easily take multiple minutes. Under load (e.g. Firefox) it would just have the same (crashing) behavior.
I have had more missed phone calls because of it, than I'd like to count.