so to wrap it up: somewhere between 45-50% efficiency + the light loss from the diffusor gets you somewhere around 35 PAR W for 500eur. buy yourself 2 cree cxa 3070 ab 3000k cobs, 2 cpu coolers, some drivers and build your own light. you can get the same amount of ppfd for 150eur max. this thing is even more overpriced than the sanlight/agriculture m30. nicely designed with good parts, but heavily overpriced.
Please do ...and bring you skills to the show mate.