The difference between using Radarscope as is and using it with a sub. from Allisonhouse is when there is a large severe weather outbreak, the public NWS servers get overloaded and that delays getting current radar data. You also get a larger looping capacity with Allisonhouse has its own separate connection to the NWS servers, so when the public servers get overloaded or even go down during severe weather (e.g April 24, 2010, the public NWS servers went down for 30 minutes around the time Yazoo City got hit by a tornado), you are still getting current radar data without interruption. I have had their $10/month plan for the last 3 years and would not do without it. Now this isn't to say Allisonhouse has its share of data interruptions and hardware failures, it happens to everyone, but it isn't often. Tyler, Gilbert, Ryan and company are on top of any issues that occur 24/7. Another thing that people complain about with Radarscope without a sub. is the lack of lightning data. Lightning data is not generated by the NWS. Allisonhouse and the NWS have to buy their lighting data from either the USLPN or Viasala, and it is VERY expensive. Like to the tune of $30,000 to $40,000 a year for Allisonhouse, and those numbers may be underrstated.
Also,on the regular data connections within Radarscope, I do not know how Imap/WDT receives its data, whether it is through the NWS severs or separately.
John