I also did the DSDse to 2v2 upgrade and agree with always_looking. Amazing smoothness and detail very un-digital. When I played DSD before the upgrade I loved it but after getting over the full rich DSD sound I felt there was something un-natural about the way DSD sounded. I have a Yggrasil and was going to sell my DAC2 DSDse but ran into a problem with my W4S Music server. I was ready to send it in until Tony and EJ got on the phone and logged into my server and fixed it. It was out of warranty (bought it used), I kinda felt I owed them something so I did the upgrade. At first I was regretting it because while the upgrade was a dramatic improvement I still preferred the Yggrasil. But I had the Recovery on the W4S powered by the supplied PS and the Recovery on the Yggrasil powered by Uptone Audio's JC2 LPS. When I swapped the Curious Cables to the 2v2 and changed the Uptone Audio JC2 LPS to the W4S it brought it a lot closer to the Yggrasil. Then I re-auditioned the filters and using the fast linear apodizing setting .... nirvana for PCM and double nirvana for DSD!!! I think it also took a while for the upgrade to break in and I chose the first filter before it was settled.
The Yggrasil has the sweetest detailed mids but is otherwise a bit thin and lifeless sounding compared to the 2v2 I am keeping the 2v2 and have no regrets. I am contemplating sending the Music server in to be able to output DSD over the I2S and bypass all the USB issues. The DSD is amazing now and EJ says it will be better over I2S. I almost have enough set aside to upgrade the server.