Geometry and construction will make much more of a difference than frame material in apparent ride quality, and even that is less of a factor than, say, tire pressure. For the most part, you will need to ride both to tell the difference, and if that difference is better or worse- very subjective thing. Assuming the same tubing thickness, the 853 welded frame will be slightly lighter just from the lack of lugs. But the tubing thickness is yet another variable. Get the new bike if it appeals to you... remember "N+1" is the number of bikes you need, where "N" is the number of bikes you have.