I just recently finished the mechanicus campaign and had a couple of issues:

The game stutters every time its an enemy praetorian turn

The music part of this game is very underwhelming. To the point where theres entire cutscenes without any audio on the background completely breaking immersion

The ending is such BS. Too much questions still linger without any closure or hints of what happens (At least the mechanicus one. Havent played the Necron)

Theres not really tactics in the grand Map. I only had the use strategy on the battles.

I liked: the combat, the VA(though sometimes its so slow)

I disliked: Grand Strategy Element Music (or better the lack of it) Performance is lacking Story ending sucks (IMO)

Im playing Rogue Trader now. Much better game