I thought I was gonna get a constant 350 ms ping (in Brazil), but as overneathe pointed out to me back then (and he was right) I got a very similar ping to US East, about 150-210 ms. I don't think I ever had lag problems on my 20-30 hours played there.
since may 15 2012 i have been playing eu servers from New Orleans,U.S.(where i live) with a constant ping around 100-150 , however people maybe confirm this ;ping has been severe SINCE the dupe in U.S. servers and after the major ban wave many people switch to EU. Ofcourse its my hunch and no1 cares why or how lag started , we only care if/when blizzard going to fix them.