I have had Oticon  OPN 1 BTEs for about four years.  While in general my hearing is improved with their use, I still struggle with word recognition.  I use disposable batteries from Costco.  Given that the price is so reasonable I see no advantage to using rechargeable batts.  I average about two days on a pair of  batts.

I use an iPhone 7 with the HAs.  I tried to use the Bluetooth features extensively for a year or so but found that the HAs became " very grabby" and tried to latch onto and take control of most communication or communication function.  I finally changed the HA related settings on the iPhone 7 to minimize Bluetooth support.  That was a huge improvement for me.