I believe these were recently released; I just picked up the 2012 model of Samsung's HW-E450 Soundbar. Currently Sears (in-store only) and Amazon have them in stock. I'll be returning a D450 which is currently hooked up, so I can provide a little bit of information about the difference between the two.
First and foremost, remotes from Samsung TVs still do not work ("C" series did, "D" and "E" do not). I was hopeful they'd have put that back in, but what they did instead was make the E450's remote have more basic TV functions. It's quite possible that will be good enough for your needs.
The design is slightly different. The (IMO, slightly awkward) angled top with the clear edge is gone -- a much cleaner design. The display is on the front. The physical buttons are on the rounded side/edge/back. It's about 2 inches shorter (left to right) and about a half inch smaller bottom to top. I also just realized the speakers are more a charcoal gray than silver. That, along with less visible lights, make it blend in a lot nicer.
There is only one optical in, the second was replaced with an HDMI in & out. There is a USB slot. The manual says you can play mp3's on the USB, and that you can connect via bluetooth also. I'm unclear at the moment on how any of that works.
With only the most minimal of testing, I believe the sound is a bit crisper. The subwoofer also has a more oomph. I've not really tested the different sound modes yet. Even though this ultimately cost a little bit more (as it's not discounted anywhere yet) my early impressions are that is worth the extra money. I wasn't 100% sold that the D450 was worth the price, the E450 certainly is.