Just got mine. Special shout out to RHA customer service for addressing the shipping snafu with me in a very satisfactory manner. Initial thoughts - build quality is superb. These things feel sweet. Awesome combination of metal and rubber. I would feel comfortable with these on wearing a suit in the airport or at the gym. Fit seems terrific and I'm usually not a huge fan of over the ear loops but these feel pretty stable. Couldn't run in them but I think gym use would be fine - lifting, cardio etc.
Now to the sound. I've used a ton of BT headsets but am no audiophile. These headphones sound very very good. I don't own the 750s so I can't compare wireless versus nonwireless. I do own the VModa Forza Metallo Wireless and countless other BT IEMs. Sound signature is warm with solid bass response without going over the top. The highs are nice but not quite as sparkly as the VModas. I might give the Vmodas a slight edge in sound quality but it's close. And if you prefer a warmer sound, the RHAs are better. The VModas are a bit more balanced with crisp treble and mids.
I definitely prefer the build on the RHA although the Vmodas offer wings for secure fit at the gym. I prefer the flexible neck band to the fixed version VModa uses. The RHA feels more premium. For the exact same price, I don't think you can go wrong with either. They are both great sounding options with different sound signatures. Also, these sound better than Bose Soundsports which I happen to think sound very good as well. These kill the Jaybird X3 on sound quality but probably won't be cross-shopped with those.
RHA, a couple of questions. Is the idea to use the clip in front just above the two electronics modules? Or is there some other place to position it? Also, I wonder about the open USB-C port and sweat? Most headphones have some sort of cover over them. Any concerns there?
Edit: having listened to these more today, I am even more impressed. Very warm and full sounding. Treble is better than my initial impressions Soundstage is more open than most BT iem. Between these and vmoda really close call. Both are the best I've heard except for maybe the beoplay h5 but they have other issues. These are keepers.