Okay, so I've installed the chainboard, but I have the same trouble as some others have had with it blocking the highest gears. My bike isn't exactly built for speed, and since I habitually spend about 90% of my time on the center front ring I'm going to ride it as-is for a while. If I find I can't live without those highest gears, though, I'll switch to the OGK.

I can say this for the chainboard- it works like a charm. No snagging, no grease, trousers are clean and un-ripped when I arrive at work.