Sorry for the late reply. Only just realised that you asked me a question.
The main advantage is to do with the impeller and fan motors. While there are 'copies' available, they quite often wont perform as quietly as they dont have the same motor.
Ive had SP120s and at the same RPMs they were a lot louder then even my new 2200rpm GTs. I could crank my GTs up and even the slight woosh the fans make would be more than acceptable to leave on 24/7. You cant do that with the SPs they even at 70% they begin to sound like jet engines
@RCoon just a heads up. Amazon are doing some arbelour abunadh in their lighting deals that should start around 7.30pm for non-prime members.
Im a prime member so if you want i can snipe a bottle or two for you - Any half decent whisky is usually all sold out/allocated before the deal even opens for non-prime members. Ive witnessed this as a non-prime and prime members loads of times
I tried to get some Macallan Gold single malt and as soon as the deal was up it was all sold out/allocated
Its currently £44-35 a bottle depending on batch. so it could drop to £30-35 or maybe even below that.
::Edit::
Its also time we started planning a uk Christmas meet up. If anyone is interested. Me and Rcoon are definitely up for it