I watched the three episodes released so far, and on the whole I enjoy the new series very much!
I'm fairly indifferent to the opening and ending songs, but I do like the instrumental music that plays during the actual episodes. I actually feel that it does fit the mood and does the scope and gravity of the story justice, although of course it can't match the timelessness and (sometimes) romantic nostalgia of the classical music.
The CGI fleets took me some time to get used to, but I appreciate them a lot more after reading an interview that explained how it allowed the production team to create the battles at a much higher speed. In that regard it really paid off in my opinion; the fast and intense battles made my heart race! It's a definite departure from the slow, often static battles of the old anime. I also enjoy the updated fleet display screens and other technology used in the battles.
As many other fans I initially had some trouble warming up to the new character designs, finding them generic and lifeless, but in motion the personalities shine through much better, and so far I'm content. I still prefer the old designs, but I appreciate these new ones for what they are, and as long as I can still recognise the same beloved characters I'm happy. I also do appreciate that DNT is more faithful to the novels in some regards; that shows how much genuine care the production team but into this.
Due to the time constraints events are less drawn out, which can be detrimental, but I reckon here it's a benefit to have watched the old anime - my memory just fills in any gaps. As long as the story remains cohesive I can forgive this, after all it's impossible to faithfully re-adapt a 110-episodes series in a fraction of runtime, and that's not the goal of DNT anyway.
On the whole I'm looking forward to the rest of the season!