Struggling vs. Tyranids subterranean assault

[Montoya]

I've been really struggling with subterranean assault.   I have tried several different detachments (reapers wager, Spectacle of spite, kabalite) and am yet to even come close in a game.   

 

Any advice?

 

I've gotten better at keeping them pushed back for the first couple of turns, but by turn 3 the engine just starts rolling over me.

[Ulfast]

I think your way are the best, just get more games into them. you will get better and better to read them.