I've owned a Filco red, Leopold red, and Rosewill black (I didn't think I'd like the heavier keys, but I had to try it). Ignoring the switch type for a moment, I personally liked the Filco and the Rosewill over the Leopold. The Leopold is, without question, a quality unit, but it has a considerably different feel than the Filco. The Rosewill had different switches making it tougher to compare, but it felt very similar to a Filco to me. It's hard to describe the difference, but I guess I'd say that the Leopold just doesn't feel as light and crisp--whatever that really means.
If I were buying a red now, I'd probably buy the Rosewill given the price/availability of the Filco. I'm thinking of getting another one anyway, actually...