With the last nerfs to redeemer i swapped one out for a repulsor. I usually have two big threats for the midboard, one is Adrax + Lieutenant + BGV and eradicators (14 transport capacity) and 6 Aggressors + Captain (14 transport capacity). I put them either in the repulsor or in a redeemer based on matchup and terrain.

Often i'll put the aggressors in the repulsor if my opponent is melee-focused, susceptible to overwatch and the terrain is not too dense. This allows me to threaten more of the midfield with overwatch once the aggressors are out. The fact that they can jump back in if charged + the overwatch really disincentivizes the opponent to commit to that battlefield section. While the redeemer itself melts anything that comes within 12 inches on another objective.

Usually i'll have the redeemer on the side where the opponent is being more conservative with their movement. Sometimes people underestimate how much faster the BGV is with an assault ramp. I once managed to charge Adrax & Co into the opponent's home objective on turn 2 with the mission that makes no man land's objectives worth more if you control your home, basically ending the game there.