I have the silabs driver working fine, used it on an older cgminer for TheRealSteve's block erupter competition.
I've not used suggest-diff but that's probably a good idea. Eligius starts out at 128, which this stick should see about 7 instead.
Speaking of which - I couldn't get Eligius to go below 127 when I tested it, suggest-diff be damned. Might have been user error, though. But if not, the pool that was used for that comp goes all the way down to Diff=2, and I'm gonna guess is currently seeing one of these miners hashing away quite nicely. Philip / other reviewers, if you'd like a user/pass, I'd be happy to set those up. Or see that thread for some other lower diff pools.
( and yes, feel free to delete this post when the time for clean-up comes
)