During my test phase (as a hearing aid newbie since October) I’ve had an Oticon Opn1, which pleased me, but then I went to testing a M90-312, which on the one side impressed me with its good level of speech understandability automatisms and its ease of use (e.g. the 2-way-buttons), but which on the other side disappointed my to some degree by the burdens introcuced with its general bluetooth connectivity concept.
For me as an iPhone user (6S+ with IOS 12.2), the MFI-compatible Opn1 had a perfectly well working streaming concept. I didn’t need the general bluetooth connectivity, which Phonak entered for catching the much bigger Android market. But I have to admit that I liked the related possibilty of handsfree usage of my iPhone.
The problems you mentioned in your post seem valid to me, but they don’t bother/rely to my own personal way of using the M90s. However, from my own subjective experience I have to add 2 other major criticisms with the M90:
the somewhat undeterministic switching of the M90 from its “AutoSense OS 3.0” mode into “AutoSense OS 3.0 (streaming)”. This happens always, when the iPhone only starts an app which later may stream audio, like keyboard sounds. IOS issues a BT-A2DP command, which makes the M90 switch into the streaming mode, which in turn makes the M90’s behavior significantly different (e.g. the mic is muted by -6db and the speech processing of the environment changes). Very irritating, especially as this happens also somewhat randomly, e.g. sometimes when no specific app ist started, but the iPhone awakes itself when giving notice of an email or appointment or such.
the handsfree feature is very convenient when making or receiving phone calls, but there is a significant downside: my phone calls counterpart (the person to whom I’m speaking) gets my voice very significantly worse (and low level) than when I use the iPhone like a standard phone (i.e. at my face, mouth/ears, with my M90s taken off). Plus there is the problem, that once I have started the phone call in handsfree mode I cannot really fall back. Setting the iPhone back to receiving my voice from the iPhones mics (instead of from the M90s mics) does also stop me hearing my counterpart in my M90. A real mess…
I’ve reported both bugs (or are they “features”?) to the Phonak development team in Switzerland, but I’m not overly optimistic, that they can solve it, due to the implicit architectural choices Phonak had to make for supporting the Android market with a general bluetooth capability instead of the limited/dedicated one chosen by MFI-compatible hearing aides like the Oticon. This will not change with the coming firmware and configuration software (Target). There they can only partially remedy my problem 2 with the handsfree default settings (mic level significantly reduced and not much adjustable by the professional via the Target software).
On the one side I would like to keep my M90, because at the very moment, it appears to be at the cutting edge of technology on the market. On the other side, the Opn1 just worked for me.