All would be better than OEM, after that they're all very similar as they all use AP discs -
The Vagbremtechnic ones Grizz fitted are AP Racing replacements for the OEM Nissan GTR rotors with a slightly different Bell to the RS6 AP one (prettier). The GTR discs are also 34mm not the RS6's 36mm but the material, cooling properties etc are still the same between the GTR and RS6 AP discs, although the thicker RS6 specific ones may last longer. The £1200 "J-Hook" version is the right price as the special grooves are expensive but the Grooved version (£1270) is just the stock AP disc and should be £800 for the rotors and bells. Someones making a lot of money there.
The LOBA ones are a custom design made by AP Racing specifically for LOBA in GTR sizes (390x34mm again) and are/were extremely expensive (£1700+) for an OEM sized replacement disc setup. However they should be miles better than OEM but how much better they are than AP Racing's own 390mm I don't know TBH as no-one ever posted a review -
viewtopic.php?f=47&t=95775
My own personal experience of the £800 RS6 AP discs (390x36mm) was that they are around 5kg per side lighter, vastly better cooled, much harder wearing and could cope with most track-days no problem so I'd expect the other 2 of the above discs to do the same.