They are most probably going to wait until the trial and migration of 4Mb users to 8Mb has been completed, then wait a few months, and only then bump up 384Kb speeds to 512Kb, and 512Kb to 4Mb.
But if they are starting to upgrade entire exchanges, then I'm sure the commercial launch isn't that far off!
So if you want to order DSL, you have to decide between 384kb, 512kb and 8mbps, wow, the gap is even bigger than the gap between the rich and poor in this country!
Next time hire someone who plans better. 1mbps, 2mbps and 8mbps would've worked much better.
Guess they keep the speed so low that users are eventually forced to upgrade to 4mb (8mb)