This issue reminded me of the series Criminal (by Ed Brubaker & Sean Phillips) in several respects. Emilio Aldrich's script focuses upon the realities of the shady side of Starling City, barely featuring The Starling City Vigilante until the very end of the issue! The artwork by Eric Nguyen is gritty and uncompromising, reminiscent in several spots of Jock's work on Green Arrow: Year One.
Your enjoyment of Arrow #27 may best be determined by your enjoyment of police procedural stories. There's very little of our hero in this issue and none of the character-based drama one usually sees on the show. Still, this issue is enjoyable for what it is - a good cop story - and well worth the $1.00 download.