A bewildering array of choices and sometimes Steve Jobs' single option "Apple knows best" can be comforting for many users. I'd bought the BlirzWolf BW-FYE1 and then thought afterwards I'd bought an old model as there was also a version 4 and 7 but getting out of the Apple mode of thinking made me realise they are choices.
I found this comparison chart that BlitzWolf has and at their budget prices, I'm thinking of just ordering a set of BW-FYE4's just to try out. It's a pity that some options use different button press shortcuts so buying all 7 could be confusing to use.
For the BW-FYE1's I have played them in stereo mode with Spotify music for a solid two hours and the batteries were down to 60% indicating they are probably good for a 4 hour stretch at a time. It's a useful benchmark to do so that you can repeat it after a year or two and see how the battery is still performing.