I also got a loaner unit of the Helios and it’s very good. Will post more comments and perhaps a special YouTube Livestream of it soon…
It’s nicely tuned, good bass quality and quantity and smooth and refined sound with gobs of clarity and details. May be a slightly forward treble presentation but nothing that is bothersome. The fit is the biggest concern for perspective buyers as it has a long, wide and angled nozzle that doesn’t quite fit well in my right ear but I’m able to get a tight seal regardless.