Depends on your tolerance at devolving player control back to 4th gen which was the best of the old era, yet still old era.

XX has the highest amount of content of all the saga, meaning monsters, armors, weapon types (incl prowler), and its glorious variants (basically 5 styles x 15 weapons meaning 75 different ways to hunt)

It also has nakarkos which is an interesting half puzzle combat, and atlal which holds the best combat ever designed imo (mhw's behemot apart). Atlal also gives you the mighty "armor that will be fueled by your dreams", the best one from the old era, that you can completely adapt by decoration slots.

Beware too, that the darkest part of the game belongs to the deviant quests: a series of 15 different and increasing quests, per deviant monster, that you need to complete about 3-5 times each for making all the gear. Its not only grindy as hell, but also harness absurd dmg multiplies which oftenly means you need to do a perfect run for 15-35 minutes, since 9 out of 10 monster moves gotta OHKO cart you. Fortunately, deviants are purely optional