I don't use it anymore, but prior to release of Anaconda (Plazma's predecessor) and MAG-10, for years nearly every single workout included personal testing of varying workout formulas. I often included arginine, sometimes as arginine alpha-ketoglutarate but more commonly as arginine or arginine HCl.
The reasons for including arginine forms in testing were animal studies indicating some possible advantage, and various anecdotal reports of benefit.
I could not tell any difference between AAKG and arginine. I don't have any impression at all of AKG being of value nor know of any study showing value. If it has value, it's from supplying a Kreb's Cycle intermediate, but for that purpose there's no indication of it being the best choice and it's certainly not the only choice. Malate for example is an excellent choice. It's likely that I already had the Kreb's Cycle intermediate area covered, which could explain personally experiencing nothing at all from AKG.
As AAKG is more expensive per gram, let alone per amount of arginine contained, than arginine itself I don't see the point really.
On arginine, I viewed it as a "why not" thing with a modest favorable impression. Not enough so, though, for me to have felt inclined to buy any in the last many years. Cheap enough however that there's no reason not to try and see what you think.
(EDIT: If already using a product with citrulline malate then I think there's no point at all to trying arginine on top of it.)