Web site: Official site offline.
Manual: Not available online.
Key Features: tilt/swivel/zoom reflector, wireless, wireless P-TTL, HSS, rear-curtain sync, manual control.
Reasons to Buy: Lots of power and features for its price. Replaced by the EF-610 DG Super now, though.
Notable Drawbacks: Older model. UI is a little rough, missing a few niceties.
Sigma's more advanced model. Replaced by the similar but more powerful EF-610 DG Super.
More about the Sigma EF-530 DG Super can be found on these pages:
Including an Amazon link on this page is the easiest way to display the current prices, without having to keep track of it manually or write a more-complicated tracking script. And as a bonus, there's a picture of the flash. Obviously, the ad is also an affiliate link. As with all advertising on this site, I hope it's not too obnoxious.