I've recently had the pleasure of trying this out. While I'm not really all that familiar with the Istanbul brand, the fact that it's a Turkish Company makes me trust it, as Zildjian and Sabian, the two most prominent cymbal manufacturers in the world, are also Turkish. This ride is 22" and is immediately distinguished from some of the brighter rides that I often hear. While it does have a nice high end, it's smoother than most. It also has a lot more high midrange than I'm used to hearing, and in fact, often seems it has a really dark sound and can really fill up space. Depending on what you're going for, this may or may not be a good thing. I'd say slower-paced jazz stuff can really benefit from this type of sound as it's full and can continue to provide a good ambience throughout a tune. Even lighter rock and folk would really sound nice. However, a hard rock type drummer would probably not appreciate this, as when played louder, it really has an unpleasant tone that tends to eat up a lot of the sound. It could work for a band that has lighter, more spacey moments, but if you're imitating Bonham this is the last thing you want. This was really apparent to me when recording, and when a drummer tried it on a session I ended up insisting that he switch it out (much to his displeasure, though he eventually agreed it was the right call). Since I'm personally a light drummer, I find it very appealing when I play it.
While the top-end Zildjian cymbals really are spectacular, I haven't found one that sounds much like this at all. Even their dark rides don't really have the aural ambience of this one. I can see why Istanbul are lesser known as their cymbals definitely have a unique flavor, but they are spectacular and this is a perfect example of their craftsmanship.