iamiam

Both DV3 & DV4 will display @ 480 pps but in recording only DV4 will record @ 480 pps. DV3 is 120 pps recording or 7 pps/channel.

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.

FYI, newer USB flash drives will not work, i.e., bigger than 2GB. Or if it has pre-installed software, you need to uninstall first.