No doubt, IRAY is a big-league player at the table of Computer Generated Graphics. As a full time architect, I have been using IRAY for 90% of my weekly rendering for the past 18months. And I must say, I'm very happy with the results. Iray does have its shortcomings, but what render client doesn't? There are times when I really want a material-ID in post production; but even then, IRAY and MentalRay play together so nicely, all I have to do is switch over to Mental Ray and do the ID pass. I have a lot of still rendering that can been seen on my personal website www.joshpabst.com
Now, we don't do a lot of architectural animation in house, but we do some. Below are some of the iray 3d animations that I have done 'not for work'. Unfortunately, some of the best work, I have of course done for actual projects, and cannon share, yet, due to project statuses.
Now, in both of these cases, the animation probably could have turned out quite a bit better had I let the animation do more passes. And, I should have. Time is always the enemy in this business. The renderings you are looking at are all less than 400passes, and especially for the night stuff, it's really just not enough. That said, when you are dealing with youtube, you can get away with it due to the fact that most people watch at 480p and not 1080p full screen.