Hi D,
Just saw this thread or I would have replied sooner. I'll be finishing the one year trial in September, so I've been on it for about 10 months. The first 6 months were double blind and the second 6 months are open label. I didn't notice any difference when entering the open label phase, which leads me to suspect that I'd been receiving the "real thing" rather than the placebo. The study coordinator had told me NOT to tell her if I noticed a difference in the powder because it had been reported that many patients reported an obvious difference. It's basically tastes like inhaling sugar, which is fine for me because I love sugar. <img src="i/expressions/face-icon-small-smile.gif" border="0">
Anyway, to answer your question... I haven't noticed any marked improvement, however have stayed at my baseline FEV1 over the last year, with the exception of one exacerbation in March.
PM me if you want any more info, I'm happy to share my experience.