Like most things we buy, it's very important to educate ourselves about the product prior to spending what could be a considerable amount of money on a cymbal. We have a multitude of people with their own opinions (remember all of us have one)  and marketing media attempting to sway our opinion on what we should buy. And they really love it when we become convinced that we just need to buy the most expensive thing out there and it's got to be great...right?...yeah right! The biggest mistake I hear of people making is that they often don't first consider what they intend to be the use of the cymbal they wish to purchase. And the first question for us gear addicts is "Do I even need it at all or do I just want it (along with all the other gear there is)?" Then determine what sound is needed from this musical instrument/cymbal. Yes, it will have a specialized purpose to provide a certain sound. For example, we must consider the difference between a "crash", a "medium crash" and a "rock crash" in the same brand and series. I'll share one quick personal experience. I have found that a 21" Zildjian A Custom Medium Ride cymbal has a very clear, cutting bell and great control.  On the other hand, the 22" has an integrated bell that can make it difficult to get that clear, cutting sound and has much more potential wash and volume. I made my choice according to my needs. Then comes what could be harder...getting to hear different options and especially in combination with what you already have. That could be at a local music store or thank goodness several of the major cymbal manufacturers have sound files available on their websites. Some of these sites will even allow you to configure setups (assuming you already have some of their brand). One nice thing about my eBay experience is that I have been able to buy cymbals (and other percussion items) and demo them and then resell them if I didn't want them. Lastly, don't assume that a certain price, brand, series or finish is the determining factor. If you look at some of the setups of the pros, you may notice they often mix finishes, series, thicknesses, etc. Yes I know appearance, brand or series matching and even the image associated with paying a certain price may be a factor. But if this is your primary objective, you may need to go back to a previous observation...do I really need it? There could be much more but I'll close for now. I hope someone gains some assistance from this guide.