A dynajet won't get you 100 miles -- at those sizes, pulsejets just don't have the necessary efficiency (TSFC) to deliver that kind of range -- the fuel payload would be too great. At 100mph it would take 60 minutes to travel 100 miles and that would involve carrying about 12lbs of fuel -- plus airframe, plus engine, plus control system (so we're talking at least 16-18lbs). No model of that weight will hit 100mph in level flight with just 4.5lbs of thrust -- in fact it'll have a hard time flying at all straight out of the launch.
Quite a few people have been flying XPS without issues -- but in those early days of magical antennas, no frequency agility etc -- lots of other people lost models to it, that is without question.
JD may have some clever people working for him -- and that's got to be a very good thing -- since he has demonstrated on numerous occasions that he has little clue when it comes to even the most basics of electronic/electrical theory. His public display of ignorance of Ohms Law was perhaps the most outstanding example of this.
Still -- XPS seems to work okay now so it's all good.