Hi Darren,
The main difference between UDP and UDP Streaming is the number of response packets the vTM expects to see come back from the node. With normal UDP we expect to see a similar number of packets in both directions, an example protocol would be something like DNS. The UDP streaming expects to see many more outgoing packets than incoming, an example would be some kind of video streaming service eg RTP.
The other UDP option (L4Accel) is for use with Data Plane Acceleration. The two options above run at the Application Layer and allow you to use TrafficScript to inspect/modify etc. The L4Accel version is for services which need ultimate performance, and the vTM does simple but fast layer 4 load balancing.
Cheers,
Mark
