The aforementioned thread is a sad deal all around.
Other than the brand that shall not be named; what other IEM unit of note beyond LZ right now? I discovered LZ from the Carbo Tenore thread, so it makes sense to ask people who like a specific sound signature what else they like. And I do like the Carbo Tenore and the LZ-A2.
If you like a2, wait for this one being released OR get A2S if on a budget.
I tried A4 against A3 and it is an improvement/refinement and you can dial the low-end and tonality/upper end with nozzles and back-plates.
Sound-stage about the same on the range.