No, never served in the military. Weapons, and especially emerging weapons technology, is simply something I'm interested in and spend a good bit of time researching. Which in this case seems to have lead to a bit too much enthusiasm for the topic on my part.
In terms of airbusting grenade launchers, other then the troops who fielded the XM25 briefly in Afghanistan that I linked to earlier, I'm not aware of any other fielding of those weapons. Experience with 40x51mm Airbursting is likely restricted to the engineers at Rheinmetal, as this is a pretty recent development of the last few years. The very first fielding of 40x51 Medium Velocity (non airbursting) was this year, to South Africa, for use in the Ripple launchers.
Outside of that, it would be the engineers at the STK who have developed their own 40x46 LVER airbursting round, and the researchers at the army working on developing the 40mm HEAB XM1166 airbursting round for the regular 40x46.
So this is really a technology where the pool of experience is pretty limited, which really limits discussion for the most part to informed speculation based on what little open source data is available.
Hence why if you have information to support that airbusting grenades don't work / work worse then impact initiated grenades against armored opponents, I'd certainly like to hear more.