okay, Yellow aircraft guy, tower might be hawking myth! then lets get some real data in here if possible like:

setup 1 Dynamax & 1 Ramtech with everything being equal! same pipe, same engine & same exaust ducting, inlet duct & same fuel.
then go measure!
1. maximum static thrust!

2. which delivers higher rpm. fan A or Fan B

3. RPM bench mark test! If "fan A' gave lower rpm, set fan B to same rpm & get trust reading for the 2 at equal rpm

4. Exaust velocity!, which one gives higher velicty (airflow measuring instrument needed!

5. Weight! which one is lighter!

6. Fuel consumption, which one gives the best economy for the same engine! (depends on ratio between thrust/rpm)

all of the data collected would give the modeller a chance to sift throught the myth & make educated choices of the 2.
eg, IF the Ramtech unit was lighter by 10% than the Dynamax, but its thrust was 4% less, then overall it might still be the better choice!
And lets say the Ramtech RPMS were higher, thus greater fuel consumtion rate, well one might want the thing to stay in the air as long as possible! so he might choose the dynamax

so anyway before i start sounding like a mad scientist, does anyone know where to find info like this or is anyone up to the challenge for the good of all rcers?
lets gets some replies on this one! yeah right!!