The only true way to tell one prop from another is to buy and fly. Prop calculators are ok if the information is entered from tested values and head to head comparisons but otherwise its mostly wishful thinking. Most every prop on the market will give within 80% of the performance of any other in the same range of size. But to see the addtional 10-15% ( if there is any) you have to bolt them on and put 'em in the air and decide what works best on your setup. I have tried Vess props on 4 of my setups and they performed very well on 3 of them, with the 4th preferring a Menz over the Vess.

On my GP CAP the DA100 will turn (static on the ground) a Xoar 26/10 @ 6800 plus, a Xoar 27/10 @6400, and a Vess 27A @6400. In the air the Vess outpulls both Xoars out of a hover/harrier, accelerates harder in a vertical than either Xoar, is faster than the 26/10 Xoar in an straight or upline but appears to be slightly slower at the top of an upline compared to the Xoar 27/10 and the Xoar 27/10 is faster in an horizontal straight line The Vess is louder at WOT than the Xoar 27/10 but not as loud as the 26/10. On top of that, the Vess gives me less wing rock in elevators and harriers than either Xoar. The Xoars are good props, If I break my Vess, i wouild fly the Xoar without any hesitation, the Vess just works a bit better for me on this plane

I wish calculators could tell me everything I just relayed here but they can't. They might help with determining a good prop from a bad prop but i don't think they tell you better from good, or best from better. Gotta fly them to decide.

take care
zonk