Yolov3 is about a year old and is still state of the art for all meaningful purposes. It's fast and works well. You might get "better" results with a Faster RCN

Yolov3 is about a year old and is still state of the art for all meaningful purposes. It's fast and works well. You might get "better" results with a Faster RCNN variant, but it's slow and the difference will likely be imperceptible. Using map50 as pjreddie points out, isn't a great metric for object detection.