We didn't initiate the comparison but inevitably similar products are being compared. There were two new reviews that came out:
This one is in Dutch but you can use Google translator to read: https://www.alpha-audio.nl/2015/05/review-celsus-companion-one-vs-oppo-ha-2/
The reviewer was surprised to find that Companion One sounded better than HA-1 that cost almost twice as much.
The lower priced HA-2 are generally not in the same league as Companion One.
I don't think the review in anyway put down the HA-2 and gave a lot of good points (charging capability, ease of use, smaller size) over Companion One.
But as I have mentioned before, Companion One is very good and a class above all other portable DAC/amp on the market.
This review (in English) also reached the same conclusion:http://www.hifisenses.com/portable-desktop-audio/subject-the-celsus-companion-one.html