As mentioned above, Saroyan is a quality brand and probably your best bet for your first pro pair. Because different materials and material density affect the sound, not all zills are the same. To demonstrate this, I am giving you the link to an online store that actually has sound files for the zills they sell so you can get an idea of what the differences mean in terms of the sound they produce (I've never used this particular site for purchases so I don't know if they are good or not but I found this particular section to be very useful!):
http://www.thebellydanceshop.com/products.php?id=18