The 896 has a small seconds and no date, while the 889 / 899 has a central second and a date.
Despite these differences, the 896 and the 899 are very close, technically.
There is no reason the 896 is better than the 899, and vice versa.
JLC preconises to set the work of your watch, if it runs too fast or too slow, which is easily done by any JLC AD or Boutique.
For your eyes only, a close up of the Cal 896:

Sssshhhh, I am preparing something on Ultra Thin movements, and I'll shortly speak abourt this Cal 896.
I can already tell you that for me, it is not an ultra thin movement, but a rather thin one. Which makes a big difference!
Best,
nicolas