Hi Agger, don't diss the Radsails for quality. This does not hold any more since they did the complete product series makeover which yielded the Radsails Pro line. You're completely right, though, when it comes to the comparison between the Radsails and the Ozone LD - there just is none, Ozone is fairly unrivalled when it comes to build quality.
But in my opinion the Radsails Pro without a doubt stand up well against the Busters, both with respect to quality and flying behavior. Nice black bridle, meshed vents, sturdy yet pretty light material and overall well sewing accuracy produce a very agile and powerful kite that does not have major drawbacks.
From the Pro 5.0 upwards I'd advise to try powerrings, however, to minimize the wing-tip-flap-in type of luffing that occurs at the side edges of the wind window.
Bye, Malte.