My men's Elysium size L weighs 20 oz (567 g), according to a digital postal scale in my office. That's significantly different than the specs listed on this site and the North Face's (as someone here also else noted).
Nevertheless, it's still lighter than TNF's Nuptse down jacket. Some of that comes from the use of Pertex Quantum for the outer fabric, which shaves off about 2 oz total weight compared to the ripstop nylon used in the Nuptse jacket.
Of the two jackets, I'd guess the Nuptse is warmer. If I were stuck on a mountain top or sitting outside for hours at a New England football game, I'd want the Nuptse. Who cares if you look like the Michelin Man? You're warm.
Personally, I've found the Elysium great for DC winters. It gets into the teens here and the jacket's adequate. It is a little less packed with down than Nuptse, but that's a plus: you can wear it a wider range of temps than Nuptse, which can get hot.
Biggest pro of Nuptse: it's better looking. It looks thick without making you look like George in the "Puffy Jacket" episode. And it has a few red styling accents -- the zipper pulls -- which make it a bit sharper than the plain-jane Nuptse. The Quantum fabric has more of a sheen than ripstop, which again makes jacket easy on eyes. My wife gave it the thumbs-up over Nuptse when trying on.
I wear a M in TNF Denali jacket but a large in Elysium so you may indeed want to size up, as someone else here suggested.