I have heard the LS28 at my dealer, I do not own one. I own a Ref 5se along with a DAC8. I like my Ref 5se much better than the LS28. It has a bigger more well defined soundstage. It also has more presence. The Ref 5 has tubes in the power supply that I believe makes a big difference. For around the same price I would opt for a used REF 5se if it were my choice. It is just superb.
The DAc 9 like the DAC 8 has a few things that may or may not matter to you. Currently it does not work well with Moon and Aurender music servers. ARC is suppose to be working on fixing the problems at least with the Aurender. Also ARC does not support Linux. This may or may not be a problem for you. For me it is. I was thing about buying an Aurender N100H music server and was very disappointed with the problems.