Cable,
My pleasure if it can help!
I tried up to 6u6 under XP and experenced execution lags etc. crap after what I downgraded to 6u5 and it fixed the problem. But I have a friend who have tried all ways including voodoo ritual dances around his XP based computer and still can't manage to make Oanda run without Java glitches.
Under Ubuntu Linux 8.04 along with Sun Java 6u10 installed I do not experience any problem with Oanda.
As for Linux itself - I like it's stability and security as first features to mention, at least Java apps run more smoothly and reliably under it for me.
Also it seems to use hardware resources more optimally...
MT4 runs absolutely OK under Ubuntu (which I use) with help of Wine (Win32 API implementation for UNIX) as well as Quotetracker does (use it with IB feed).
Not that XP was a nightmare, it was OK, but Linux definitely is what I like - gives a stable, secure, easily configurable environment for free... So just see no reason to help MSFT go up by buying their products.
P. S. I am also very interested in how you use MT4 with Oanda feed.