Low Noise LFA Yagis, there really is a difference!
Normally I like to write something of length but this time, I will let the real world results do the talking. Below is a link to a video created by Jarek, VA3NCD who compares his 7el 50MHz G0KSC LFA with a well-know, commonly used, US built equivalent.
First Jarek simply switches between the antenna with just background noise only. Move forward 4 minutes in the video and Jarek points his beams at different beacons and conducts the A/B tests. Note how marked the audible difference is in noise this is 'many' DB's difference in noise floor and as you can see from the beacon tests, makes a difference between Q5 reception and not being able to copy a beacon at all.
Many antenna designers display antenna comparison plots against my antennas showing the similar patterns. However, the LFA is not a spot-frequency antenna and performance difference is not attributed to pattern alone. The LFA is a wide band antenna in terms of performance AND SWR. Many antenna vary greatly in side lobes, F/B and gain over a short frequency range and thus, the LFA has predictable performance everywhere. Next, the low noise characteristic is not a result of pattern alone, the closed loop driven element adds to this characteristic and reduces the noise floor and has a direct, 50Ohm feed point so any matching losses (whcih includes additional noise) are not added to the antenna after model.
Have a good look through this video and see the facts in the real world!