To update, my fence came in yesterday and I have it installed and dialed in. Very easy to assemble the extrusion to the t-square mechanism, but I'd suggest watching the video at VSCT for several helpful tips. After that, adjusting it parallel to the miter slot and square to the table top took all of about 10 minutes. As someone mentioned earlier, it fits the SawStop T-Glide rails perfectly. (Won't fit the other "Premium" fence rails.)
The extrusion is plenty straight for me. Using a dial indicator, I see a 0002" variance over 42", well within the advertised claim of .0001" per foot.
There is one area of possible concern: The extrusion rides across the table on a small piece of UHMW that's about 1/8" thick, which means there's a 1/8" gap under the fence. Not good, if you're cutting very thin stock. You can't grind/sand the piece down, because it's held in place with a countersunk flat head screw. I've ordered a couple pieces like the SawStop uses, which are thinner and adhesive backed. For now, I've put some slick tape under that end, works fine.
In all, I'm happy with it. Allan (VSCT guy) and his wife, Sue, seem like nice people and responded quickly to a few questions I had.