MJPEG streaming in general is really resource intensive versus H.264 streaming. It is fat and H.264 is skinny with meaty algorithms.
Some cameras also only let you do either MJPEG or H.264 but not both at the same time. Thinking that the Hikvision lets you run the MJPEG sub stream at a lessor resolution than the primary H.264 stream but I never played with a Hikvision camera. Just reading this some where.
The above noted I personally would recommend using JPG streaming (quickie snapshots) and you won't be able to see the different on the tiny 640X480 resolution image on the Omnitouch 5.7e. (well I cannot here see much of a difference). I do not notice a stutter in the video when an automobile comes up on the driveway.
The main difference between H.264 and MJPEG is that MJPEG only compresses individual frames of video, while H.264 compresses across frames.
MJPEG is the compilation of separately compressed JPEGs in a sequence, which leads to high quality outcome in terms of resolution.
With H.264, on the other hand, only some frames are compressed by themselves, while most of them only record changes from the previous frame. This can save a significant amount of bandwidth compared to MJPEG (which encodes each frame as new), but results in a video of lower quality.