Matrox makes a lot of out of its true multi-display support for Windows 2000. I say quality is all important when it comes to any multi-display solution; Matrox' pedigree in that area is pretty good.
3D performance should see a 20% improvement over G450, and frankly, for the casual gamer, that may be a non-issue. That's a debatable point - sometimes people buy products as much for the promise of something as the delivery. One thing that Matrox does have going for it is that it is a stable supplier, has been around for some time, and like I said, has a large installed base. Corporate fans of Matrox may not be as concerned by the 3D implications.
On the other hand, the G550 seems a little forced as a product release. It's more of a quick refresh of the G450, and may very well be a stopgap measure for Matrox. For a number of years, Matrox' competitors have been talking about a Matrox 3D product that would put Matrox back in high-end contention, but that's a longstanding rumor.
Certainly, what made Matrox its fortune was the fact that its Millennium boards ended up in the high-end and workstation PC lines of the tier one OEMs. In 1997, the year of Matrox' $690 million sales, for every single OpenGL 3D accelerator board that was sold into the NT workstation market, you probably would have had 10 Matrox Millennium boards being sold through the same OEM. That's Matrox' market. That's where Matrox excels.
The G550 isn't the product to get Matrox back to those heady days, but it certainly is a high-end 2D product in an era when 2D doesn't get enough respect. We'll have to wait until we get a board to review to see exactly how acceptable the level of 3D performance is going to be, but in the meantime, judge the G550 on its own merits, and not the HeadCasting blurb, or its 3D.