So I just tried Orbiter 2010 on an XP guest with VMWare's free VMWare Player 3 software. The guest OS was allocated 1.5 GB of RAM, and of course VMWare's 3D acceleration options were enabled. All the other hardware specs were the same as my last run.
Using the DirectX 7 client, I got pretty poor result. The most noticeable is the rendering of stars: they come out as massive gray blocks that fill the sky. Frame rates were pretty poor, as well. I think I saw 6-7 FPS, max.
Next, I tried Artlav's OGLA client. This worked significantly better. I was seeing upwards of 70-80 fps, probably with an average of 30-40. Not great, but playable. The rendering was mostly flawless, and some aside jerky motion aside, it looked fine. I was going to post a screenshot, but there's no point as it looks just like a normal Orbiter session. So "good job" to Artlav, I suppose.