The comfort, style, and shape of a seat to suit you, really depends on you, and you alone. We all have different anatomies, different bikes have different types of seats, and what works for one, may not work for another...even with the same brand of seat. I have owned a few Corbins, and they were all miserable bricks...to me! Others have praised them to the heavens. I think the stock Spyder seat is one of the most comfortable I have ever experienced, others were in pain from the moment they sat down. I have had bikes with very nice aftermarket seats, but have tried a Sargent and a Day-Long on my BMW, and they were both too wide and put my legs to sleep. Of course the Spyder poses fewer problems there, since you never put your feet down.
My advice is to try to find someone nearby who has one or the other, and ask to sit on it and try it. Maybe somebody on this forum can arrange to meet you. Only time in the saddle will answer your question accurately. Even then, someone else's Day-Long may not be quite right, since they are custom built to suit. If you must buy one without trying it, I'd probably choose the Russell. It is built to suit you, from pictures and data you submit, instead of being more of a standard seat. Better chance to get it right the first time. Not throwing rocks, some folks are very satisfied with the Corbin.
-Scotty