Pretty interesting. I'm typing this on my RMBP right now with Photoshop, Illustrator, Parallels, iTunes, and a dozen other applications open, and I've not noticed any sort of graphics limitations which are giving me any real-world fuss. Scrolling web pages has actually been a pretty smooth experience (maybe I'm missing out on some of the pages that are causing trouble). Upon reading the article I did try CTRL-zooming in and out on the page and that's not buttery smooth, but definitely more than smooth enough.
I definitely expect that any small performance issues are going to be cleaned completely or mostly in Mountain Lion.
As for scrolling, when I first started using the computer I did notice that it seemed just a touch less responsive, but now I can't even notice it (even switching between my Mac Pro and the MacBook Pro I just replaced).
I can't say the same for my Cinema display. Switching back to that after using the RMBP for a month was... jarring.
If someone's interested in buying one of these machines I definitely wouldn't get hung up on this little MacRumors article. Nothing mentioned here has given me even the slightest bit of trouble. Using this computer is a dream. It is the most enjoyable Macintosh I've ever owned.
As for AnandTech, their articles on the RMBP are fantastic. If anyone's going to take something away from them, they should read the full articles, not just snippets turned into sub-stories by third-party sites.