Of those two I would have no hesitation at all in suggesting the Holydiver.
I am a huuuge fan of the RY. That is known. But in a superstrat you need to have a specific sound in mind or a darker amp/cab to make it shine. If you have that, go right ahead. Otherwise I am inclined to once again go with Slarti here. The HD is amazing in superstarts, splits well, and, while being warm and musically rounded, it is not as dark as one might think. The top end is there. The HD likes brighter axes and the RY darker ones. One does strats, one LPs.
I had a RY in a very light superstrat and it nailed a certain sound with my setup. But now I replaced it with the way darker and warmer Crawler and I am overall much more happy.
My HD meanwhile is great, but as the guitar is rather on the dark side I am at times tempted to replace it with something brighter.....
Anyhow, rambling again. When in doubt: HD here.