JV Series has MJPEG compression and Global Recording, meaning even if you set it up as Motion Recording, all the channels record if 1 channel detects motion. DV3 & DV4 has MPEG4 compression so you'd have longer storage capacity.
240 FPS DVRs are going to be more than your budget. I would look for 120 FPS models where you can allocate frame rates among different cameras. This way you can set some cameras at 30, and lower rate on less crucial areas.