Hmm...
Hi Marty. As you might expect, I have the full set installed here (SS06, Add-on, extra missions etc, 2008, V1.3 with 2006=>2008 convertor pack.
I'm running it on XP and haven't noticed that effect. I've just turned this PC into a Vista dual-boot (so I can upload my missions!), so I'll have a closer look. Maybe I just haven't noticed it, but it certainly isn't obvious on my PC.
Missing the polygons usually means that there is a coarse appearance as usual from far away, which doesn't improve as you get closer. I know they had to cut the numbers down, but perhaps there's more to it.
I know that some things are missing completely, but that's not the issue here.