X-Crafts has some very sophisticated modeling but till now no FMS SPD or HOLD functionalities available (i.e. missing some FMA modes), they've internally tested FMS SPD for long time but not released yet. FPS has some better systems, but LNAV is still bugging and VC modeling is quite not good.
So if u are going to fly on vatsim or airports mainly use RNP(-AR) approaches I would like to recommend to wait further.
just checked their discord server, now I believe it's a pretty bumpy debut for A300 today lol, some 70(and increasing) support requests were posted on discord alone, w/ a number of malignant bugs identified.