In practice Faster R-CNN worked better for me than YOLOv2 as it, in contrast to what is reported in the paper, had a higher recall for the detect task I used it for.
LSTMs are on their retour in my opinion. They are a hack to make memory in recurrent networks more persistent. In practice they overfit too easy. They are being replaced with convolutional networks. Have a look at the latest paper from Facebook about translation for more details.