Anni 23 is definitely one of the best all-rounder. I also noticed the recent popping up sales, but the second-hand price is still very strong, compared to other recent hyped IEMs.
Regarding bass, it is of course subjected to personal preference, but to my ears, I feel the same level of enjoyment of bass as my Z1R though they are not the same. One example of bass preference is those who like CFA Bonneville, which I happened to be one of them: Bonneville is very mid-bass focused, unlike Anni or even Z1R in that regards. Somebody mentioned lack of detail and texture of Anni 23's bass, but I don't feel that way.
Anni 23 is absolutely one of the best in terms of detail retrieval, I can hear a clear difference between Anni 23 and my Z1R. The detail retrieval of Anni 23, however, does not give you any cold analytical feel, on the contrary, Anni 23 is very engaging and entertaining.
As a potential buyer, I do hope selfishly that the second-hand price will collapse and I will get a bargain, but I don't think this will happen in the near future.