When it comes to talking about the early seasons of 'Law and Order', 'Special Victims Unit' and 'Criminal Intent', those for 'Law and Order' were to me the most consistent in quality. Seasons 1-10 had some disappointments but were overall of a solid standard, whereas 'Special Victims Unit' was already inconsistent by its Season 7 and 'Criminal Intent' for half its run (both with outstanding episodes, but when 'Special Victims Unit' in particular missed it misfired big time.
Season 11 was a hit and miss season, and the start of when 'Law and Order' started to not be as strong as it was. It did have its winners though and "Brother's Keeper" is one of them. Reading the synopsis, it is a plotline that could easily have passed for an early seasons episode. And the episode in quality is pretty much likewise on the most part, and this is meant as a good thing and not in any way suggesting a going backwards in development quality.
"Brother's Keeper" succeeds in almost every way. Jerry Orbach and Jesse L. Martin are such a fine pairing, my personal favourite actually of the police pairings and the one that settled quickest. Both of them are reliably excellent, particularly Orbach on suitably gritty form (something that he did so well). Michael O'Keefe plays his difficult double role expertly, no easy picnic playing dual roles and O'Keefe's portrayals do disturb without being too obvious.
Production values are slick and professional, not ever resorting to cheap or untested gimmicks or anything. The music is haunting in the right places and isn't constant or too loud, and the direction gives the drama urgency and breathing space. The script is lean without being over-heated and while there is a lot to digest there is no extraneous fat.
Also had very few issues with the story, which had tension and constant intrigue. The conflict doesn't get confusing or predictable and has suspense, the dilemmas that come with getting results and how the case is complicated are insightful and handled tactfully. It is not simplistic or convoluted, even with a lot going on and with being quite intricate.
The final quarter is slightly rushed and over-stuffed, not uncommon with 'Law and Order'.
Otherwise, great episode and one of the season's best. 9/10.