Reviewers rarely discuss bluetooth headset audio qualities - unless these qualities are somehow deficient.
You don't need "audiophile" quality for phone calls. Any standard Bluetooth headset with adequate range and battery life will do. No point in having better fidelity specs on audio input and audio output hardware if the expensive excess will all be lost anyhow - the phone's internal codecs and the network's encoding protocols are the maximum "real" quality anyone can hear across the phone.
You might want better headphones/speakers if you listen to music or lengthy audio presentations. You might want to ensure you pick headphones with minimum lags and latencies if you do online gaming chatter. You might want to ensure your headphones have good selection or filtering features if you plan to use them a lot in crowded environments (especially in crowded environments where everyone else is crowding the Bluetooth radio channels).
It's a market full of crazy hype and advertising. Simple fact of the matter is that these products will last a while but they're basically disposable. The super-cheap dollar store brands are garbage. The super-costly elite brands are essentially a waste of money (unless you understand that you're buying fashion, not tech). The products in the middle tiers are fiercely competitive and basically price themselves so you basically get exactly what you pay for. Just decide how much you're willing to spend, which brand(s) you prefer to include or exclude, what style and colour you like, make sure it works with your phone before you leave the store, and you can't go far wrong.
