(Sorry to rehash this, but for just today I have an A4 and AK right next to each other. Both with the same settings so I am doing some A/B tests with my ears.)
Doing some A/Bing of the same kick patch and yes A4 and AK sound different. AK is clearer in the highs on that patch, ironically. More of a finished sound. A4 is woolier.
On 2nd kick patch test, the differences are more apparent. AK circuits have more of a scooped (lows are higher, and treble higher) frequency response. A4 is less so (more mid forward).
On fat, moog-ish bass sounds, it’s a bit different since those sounds don’t have the high frequency attack content that good kicks do. So the bass bump is more noticeable on AK, for sure. A4 sounds more mid forward, again, with good mid presence for bass lines. They are objectively different - but I think neither is objectively better. A lot of times, in production settings, forward mids (A4) are a very desirable thing in an analog synth.
More to the point, these comparisons are with the exact same parameters on each machine.
When moving beyond the differences, we must also examine capabilities. I am finding that with some quick use of high resonance HPF or even using the peaking filter, I am able to get that same bass bump out of the A4.
And inversely, I can get more forward mids out of the AK when using the peaking filter.
While these two synths don’t sound exactly the same, they are equally capable.