I am happy that your waiting is over
. So to your questions:
I find 445 tuby as it is very clear, detailed and has a exceptional stereo scene. Meantime it has (with acoustic music) not a weakness of for example 300 B as it has good bass and clear highs.
It is not ''tuby'' in the sense of thick and slow. With totaldac i do not find it lean either, it sounds simply naturally.
I find kondo souga warmer and very slightly slower. It was not a matter of class but taste. I prefer 445 with abyss.
I can not answer your questions concerning dynamic HP good, as i only have one pair (LCD-XC). Here i do not think it is pretty similar. (with and without 445). Totaldac drives abyss very good (via xlr) assumed you do not hear too loud. But if you want to hear what abyss really can you have to hear it pretty loud IMHO, and i find if you can afford 445 the difference is worth that money.
I have contacted many known audiophiles (some reviewer, and people who heard many expensive DAC-s) before i bought totaldac.
See f.e. here:
http://www.whatsbestforum.com/showthread.php?6905-Totaldac-Reference-D1/page16
and keep in mind that was ''only'' the DAC without reclocker and streamer which really make a difference.
I have not heard streaming clients throw it, but i find app /application and ease to use it simply excellent.
The only thing to criticise an 445 is how it looks (but on the other hand it fits abyss which are not a beautiest HP too
)