I've had a Venus 15 and a Hermes DDC since the beginning of the year. I noted that one particular 24/96 Qobuz track of female choir had some stridency. It is now almost gone. It could be due to the BluOS upgrade I did last night for my Node 130 streamer, or due all the components and cables breaking in more.
I saw a video with Alvin Chee of Vinshine in which he explained that the Hermes was the sensible DDC to get for the Terminator 12 (which is the same as the Venus 15), so there may be no need to go for a Gaia with a Venus 15. If you play CDs, it might make sense to get a DDC anyway. I don't know about the need for it with a higher quality streamer.