The DAC is 8-bits on the Q43. It's the ADC that's 12-bits (same as the K42).That PIC18F27Q43 looks like a nice part, with a 12-bit DAC
The Q43 is similar to the K42, but has "more" peripherals (4 uarts, 3 NCO, 8 CLC, 16-bit PWM).
One nice thing about the Q43 is that the peripheral SFR registers are located at the bottom of memory in bank 0. On the K42 they're up at the very top, which puts them out of reach of the MOVFF instruction, and you have to use the new MOVFFL 3-word instruction to get at them (slower, more code).
It also tends to be a tad cheaper (and right now more available).