Please remember that the Lemania CH27 movements came in the 5070 series of the late 90s - early 00s. But pressure was put on Patek by Lange with the movement in the Datograph so they had to try and compete technically, hence their "in-house" movement which debuted in the 5170 series. Regardless of this, the Lange calibre is still superior in quality, architecture, etc...
Current "in-house" calibers are also produced in higher number due to production capabilities while the Lemania caliber was limited due to availability.
Again, it comes down to what you like and what you want 😉👍