All-in-one integrated, 10-15K range, class A/B only

Pass labs-INT 250
Luxman L-509X
Boulder 866
Cannot go wrong with any of those. 

If you want to save money, go for Naim Uniti nova. I have it with aerial acoustics 7T and 2 REL S5/SHO: Love it. 
As people above have mentioned, it depends on speakers. 

Another vote for Luxman L-509X. Pair it with Lumin T2 or Aurender A10. 

You should audition Luxman 509 or 590axii.
I was also looking initially for all in one and hence bought Naim Nova. I was running (still run sometimes for a change) my aerial acoustics 7T with Naim Nova. I love them and still have it, probably will keep it. I recently bought Luxman 590axii, as I wanted more musical class A tube like sound. They are end game amplifiers. They have not even broken and am already in love with it. They are different level all together. They are more than sufficient to power any speaker with decent sensitivity. Their rated 30 watts is very conservative. I am using Nova as streamer/DAC to Luxman 590axii. Eventually I might change Nova to reference quality streamer/Dac. I am now researching which streamer/DAC to buy. The idea of all in one is always intriguing but I am settling for streamer/DAC and integrated amp combo. Again, keep Luxman 509 (if you want more dynamic sound) and 590axii (more musical) in your list. 

I am no expert, but dynamics is more to do with clear delineation across various dynamic spectrum of sound (soft to all the way up to loud notes). Little bit more analytical and may be more definition of every spectrum. Yes, musical is very smooth, without much emphasis of clear distinction of various notes. Just melowy and emphasis on high and mids.