I have the LA4 + AHB2 mono with KEF LS50 Meta + KC62 sub. I also have the DAC3B in the system but only use it with a tube headphone amp.
I would not recommend the DAC3B over a slightly warmer DAC such as the Pontus. Though that would depend on how bright your speaker is. With my neutral sounding LS50 Meta I liked a bit of warmth. I used a Musetec 005 DAC and it was excellent. I sold the Musetec to raise cash for a used Lumin X1 and that is the best match so far with the LA4 + AHB2 + LS50. The X1 is in-between the Musetec 005 and the DAC3B in tone.
If I cannot swing the $$ for an expensive DAC I am looking to buy in Sept, I will buy the Musetec 005 again for the Benchmark system and use the X1 on the new Livingroom system (my original plan).