Seagull 78 is a great product. If you're one who swaps out controllers often, or utilizes a AtariVox, you can interchange devices with the Seagull in place seamlessly. Literally, all Genesis compatible gamepads and joysticks instantly can be used with the 7800 with no modifications required, having buttons B&C mapped to 1&2 respectively. Highly recommended.
Space has been the only real determent from obtaining a full blown joystick controller. That easy to change 4-way to 8-way switchable controller is very appealing though. I have to admit, a little envious of sramirez2008's setup seeing his post above, and have no doubt my review would be similar. Top-notch quality, indeed, comes with Edladdin products.
A little out of the realm of the 7800, but still related to classic gaming, and certainly inline with the topic, Ed goes way above and beyond in the customer service area for other platforms too. It would take a book to write up the amount of support and research that went into troubleshooting and rectifying some corner case games with the ColecoVision controllers in making them as compatible as possible with all titles available.
The amount of work, including hardware workarounds and replacement/alternatives offered, was almost overwhelming to read alone. Fantastic communications and very transparent dealings. Understandably, on the surface, the casual gamer may balk at the notion of paying $XXX for a joystick, but you'll be hard-pressed to find anything that comes close to the workmanship and support that comes with purchasing an Edladdin controller.
Read through this thread and it's all you need to know about Edladdin's work ethic and delivery of quality products.