@jaded Griffons do come later
I have ran into a few heavies, a grasshopper, a jagermech, some Dragons, but for the most part, I am I think 80 odd weeks in now and I haven't seen any of the big nasty mech's yet. Centurions are deadly, Jenners can be scary in numbers. The biggest thing about the ShadowHawk which is making it very nice in the game so far is it's speed, 5/8 with jump jets is nice mobility.
I am running two ShadowHawks in my main lance right now, both are loaded near max armor 4 jj's, a large laser and an LRM-15 each. How you customize your mechwarriors matters a LOT.
It is imperative to put split fire mechwarriors into those shadowhawks to make sure they are applying full damage constantly and when heat gets high, melee attack to cool off.
Accompanying those two shadow hawks is a hunchback which I stripped the ac-20 out for an ac-10 (more ammo/range and ac damage is beefed up in the game compared to tabletop) and a pair of medium lasers with max armor and some jump jets, and a Trebuchet I've kitted with an upgraded zeus lrm-20 and 3 medium lasers. The hunchback is the slowpoke at 4/6 but it's been working well.
Sometimes you have to chase vehicles down (and my god, kill those first, they can do tremendous damage but are usually pretty fragile, especially if you can get up on them and melee attack them) and on those missions I usually bring a jenner or a firestarter.