To many the Rolex Daytona SS 116520 is the most sought after and difficult to source piece in the current lineup but the truth is, they are no longer as in demand as in the past due to the economic crisis. The collectivity factor for SS Daytonas essentially stemmed from the Zenith Daytonas. Before the Zeniths were the Val Joux movement plexi Daytonas and today command a high valuation among them. But at that time, they were a flop for Rolex; they had lots of trouble selling them and appealing to the public. Thus, when the release of the Zenith Daytona came along, Rolex produced a very low number of them especially in the beginning to prevent excess inventory and the same error they made on the prior models. At times, many AD's had trouble obtaining them and in some cases, waiting lists were as long as 7 years. As we all understand the theories of supply vs. demand, there was of course and excess shortage of supply and high demand. And as demand grew, so did the value and reputation of the SS Daytona in the watch world.
But as the newest models became more easily accessible to customers, the demand for them has also declined. Today, many collectors prefer the Zenith Daytona's over the in-house movement. In addition, I believe the dials both black and white represent a much more aesthetically pleasing dial. The color contrast between the dial and sub dials are just gorgeous and simple. I have personally gone through a number of Zenith Daytonas myself and are still one of my most favorite Daytonas ever made.
The Zenith Daytonas were produced for a little over a decade and during this time there are a range of dials variations that made them very collectible with the mid-90's and later versions on the lower end of the spectrum. The very early models such as the Floating Cosmo, 4-liners, Patrizzis, and Arabic dials are considered the most collectible and valuable of the bunch. But within the bunch, the most elusive and valuable of them all would be the Porcelain 16520 Daytona. These were only produced for a very short period of time and extremely rare.
The R-series being the first of the Zenith's, the porcelains were only produced only at the very beginning of the R-series. Estimates have been estimated about 50-100 pieces ever produced. Of course these are only estimates as Rolex never releases production numbers. But several well known international collectors have stated these numbers. The dial was actually layered with a coating that made the dial look "porcelain" and letters were printed on top of the coating. This made the font and print almost looking floating in mid air when examined closely. In addition, the black font almost looks darker and more vibrant than the regular production dials. The intention of Rolex producing the porcelain was because it made the watch look more appealing when photographing. But after a very short period of production, the process proved to costly to produce and they switched back to the traditional dials without the porcelain layer.
Over time, the Porcelain 16520 is considered to many as the "Holy Grail" of Zenith Daytonas and there is good reason to that claim. Values of these have remained extremely high and I see it continuing to hold their values for the future.