Sure enough, what they ate affected the levels of fatty acids in their blood. Now since fish oil is the fashionable supplement, as Ray Peat writes, this study primarily looks at what happens to the omega-3 (n3) levels in the blood, but it reports all the changes. So you'll note that n3 goes up, and levels of the omega-6 oil linoleic acid goes down in the grass-fed group.
Grass-fed meats all taste better, which is a sure-fire indicator that they're more nutritious. I get pastured eggs, chickens, turkey, and pork, where possible. But, that said, if you're on a budget, avoiding the grains (especially wheat) and veggie oils (rich sources of linoleic acid) is going to be the best bang-for-your-buck to improve your diet. Ned Kock posted a comment with a link to his post comparing the linoleic acid levels of grain-fed beef to vegetable oils. Suffice it to say, if you're buying grass-fed beef to improve your fatty-acid profile, and still eating veggie oils, you're wasting your money on the beef.
I'll also note that I posted back in October an analysis of a bunch of statements by Dr. Comerford, a "scientist" who said:
"We in the academic community should be very careful crediting grass-fed beef as a healthy product to humans. I am a preponent of the product, but I also know there is no scientific evidence to support grass-fed beef as any more healthy to humans."
I was pretty dissatisfied with his statements then; the post was titled "Scientists and Statements Unsupported by Evidence". There was evidence back in October that he was blowing hot air. Well, now we have some more evidence.