Masquerain has access to a large range of moves to cover various types, that aren't typical of a bug/flying type.
Its movepool includes:
-Access to water moves such as scald and hydro pump deters all but bulky fire,rock and ground types looking to land a super-effective hit. Scald burns are devastating for any physical attacker.
-It has access to energy ball (and giga drain through ORAS move tutors) to threaten water types, in addition to rock and ground types once more.
- Sticky webs is an amazing entry hazard which lowers the speed of the entirety of the grounded team.
- Although a physical move, Lunge and its ability to lower to attack all the time combos with intimidate well,and pressures physical attackers to switch,particularly when running roost as well ( note that rock moves will deal 50% damage on roost turns when the user is slower than masquerain.
-Stunspore is nice for things that don't care about burns.
-Mudshot always drops speed. Slap groundium onto masquerain and you have a quickfire way of dispatching of heatran,a common stealth rock user and switchin.
- Quiver dance can more feasibly set Masquerain up to sweep weakened teams, due to its gen 7 stat buffs (see below)
Concerning its stats,they have been improved in the most recent games:
-It now has a new base speed of base 80,and not 60.In higher metas, this allows it to outspeed and threaten OHKO on a max speed adamant landorus. As both mons have intimidate(Masquerain's unnerve also works), you can also safely scout the landorus' speed through the order the ability activates.
-A base 100 special attack stat as opposed to 80. With webs up, and its coverage all considered, it now has the ability to threaten a KO on a lot of things.
-70 / 62 / 82 bulk isn't great, but you can take a few hits factoring in resistances and intimidate. It only has 3 resistances and 1 immunity, but two of its resisted hits only deal 25%,and its immunity is to ground type attacks,great with earthquake being common coverage(beware of potential rock coverage alongside ground though).
I personally feel Masquerain should always be running max speed timid, then enough power to threaten stealth rock setters second.Stealth rocks particularly hurt Masquerain,but it's fortunate to have stickywebs and such a great arsenal of moves to help prevent them ever going up.
I doesn't like steels or fairies in general before a QD, particularly the four landspirits which are everywhere these days,so teammates are needed to help cover them.