Bit late but I watched the first two episodes of this last night. I wasn't sure about a spin off at first but actually given what felt like an Alicia's increasing ambivalence towards law in the last season of The Good Wife it kind of made sense.
Really enjoying it so far Lockhart is shrewd, intelligent but also perhaps slightly a more sympathetic antagonist than Alicia and it gives the show an overall different feel particularly when considering the moral ambiguities inherent in practicing law. Reddick, Boseman, & Kolstad feels far more fresh and interesting as a firm than Lockhart, Decker and whoever else was at that firm (how many named partners does a firm actually need).
Not sure about Rose Leslie so far she sounds a little bit robotic?