I have received AM16 balanced today (8 days since the order, 7 days since shipped by kztws - nice, a good reason to pay a bit more to them -$56 for the balanced for the records).

Here are the bass and balanced versions of AM16 side by side with the same/matched cable (a nice emeralrs/jade one for the 'best possible cable tuning" from KBEar/KeepHiFi).

The same signature of "AM16" on both- try to find a very subtle difference - your audiophile quiz of the day

Main comparison of the two AM16 is clearly with AS16 Pro X - the previous pinnacle of the same driver count.
Our 120+ year old grand piano is acknowledged for the photo-ops
Well, what can I say in few words - for me, balanced makes all the sense, as
@FreeWheelinAudioLuv2 smartly pointed out - the balanced is the way to go with KZ (and I am a bass-lean person for the records). Then, I did read the feedback on KZ thread that the bass one offers not enough bass for some. I can't imagine how it can be - but preferences do vary, as well as tips and sources.
To report mine - wide-bore TRI Clarion got a very good seal for me, and made all frequencies thrive well. Questyle M15C as a source helps a lot with the agility of the bass. (This source may be a bit too much for all-BAs, but I just loved it with hybrids and used for this comparison for simplicity).
The balanced AM16 is my preferred bass levels. I was silly in a retrospective to order bass version first, but is/was very much happy to experience it.
AS16 pro X sits in between AM16 bass and balanced with the bass level for me. The metal nozzles of AS16 Pro X (and many older KZ) is what I miss the most in new KZ. AM16 got a new transparent resin matrix, surely looking nicer, if it is important to you.
Treble is a bit more refined with AM16, as well as the mids are more present with AM16
If you thought that more bass could work better for your AS16 pro - bass version of AM16 will deliver more!
If the bass was a bit too imposing with AS16 pro- then AM16 balanced will do well.
AS16 pro went as low as $35. Is $50-60 price for AM16 justified - yes, for me. If you can snap AM16 at around $45 or so- it is surely a great deal, IMLO.
P. S. AS24 and Sonata are a bit at the different level for me. I thought to include them in the comparison, but they are different - more bass lean, subtle, just a different design for a different sound signature that resonates more with me for its subtledty and refinement, while AM16 is surely more engaging IEM and great at $50 or so.