It looks like the term "new Twitter" will soon have to be retired (at least until the next major overhaul). The rollout that began a month ago has been finished, meaning every single Twitter user can see what can now be accurately labeled "current Twitter."
Twitter considers this a major success, and since not too many fail whales showed themselves due to the launch, that seems like a reasonable conclusion from a technical standpoint. As for a more subjective evaluation, Twitter's Carolyn Penner had something to say.
Penner wrote on the Twitter Blog earlier today, "We've received lots of great feedback that will help as we continue to make Twitter.com even better. . . . So while we still (and will always) have plenty of work to do, we're pleased with the positive reaction so far."
If you happen to feel differently, or at least don't want to get acquainted with the new Twitter just yet, the old layout is supposed to remain available for a few more weeks.
Then it'll be "current Twitter" all the way, which could provide a nice platform for new CEO Dick Costolo to make more of an attempt to monetize the service.