Is your Roubaix an aluminum frame (I thought they were steel)? If so, I'd guess it weighs in about 3.3-3.5 lbs. Either of these steel frames you're talking about weigh at least 4. So, you are going to go up in weight. You will gain in comfort though. If the Eclipse is Reynolds 853 tubing, it is the clear choice over the Soma's Tange Prestige steel.

You might consider looking around for a titanium frame. You'll get the best of both the steel frame and aluminum frame. Aluminum- lightweight, steel-comfort. Ti has both characteristics and will outlast both.

Ti frames from about the same vintage as your Fuji can often be found for $500, often less.