You guys will get a lot more info on 3/25.
But for those keeping score:
1 - ?
2 - 250D
3 - 350D
4 - ?
5 - 550D
6 - 650D (nearing EOL)
7 - 750D
8 - 800D (now EOL)
9 - 900D
The 650D is 3 years old and very large and expensive for a mid tower. The 750D effectively replaced it, with more capabilities for less money. Sacrificing two features of the 650D (hot swap dock and side panel latches) we were able to make a REALLY good full tower for the price of a high-end mid tower. And you guys have responded, the 750D is flying off shelves.
However, the #1 request for our Obsidian line (aside from Mini ITX, which we just launched) was a new mid tower to replace the 650D, because the 750D was too big for some. So we took a look around the market, gathered up some competitors' parts in the lab, did some testing, and developed something new. I think you'll like it. Though it'll be priced similarly to the H440, the focus is completely different, as that's their quiet product line, and really designed to kill the Define R4 from Fractal (and good luck to them! the R4 has been a monster for years! It'd be good to see some change.)
If you like the 350D and the 750D, but want something in the middle, I think you'll be very happy on 3/25.