So we're in the midst of beta testing CF4.0 right now, and I have the same build running on my Win7 x64 dev box, a 400mhz WinCE 5.0 device and an Atom board running Ubuntu Mavierick. The overall look and feel are pretty darn close. It's actually pretty cool!
Now the reality is that other than basic media playback and some web apps, there's not really much in the way of apps for CE or Linux (right now). And I really don't think there are any plans (as far as I know) to release the linux version to the retail market (OEM only), but that could certainly change at any time. In my opinion, this is an absolute "good thing". Having a common code base and SDK makes delivering custom solutions a lot easier (something I do), and the lessons learned work their way into the Centrafuse core, which benefits everyone.
I'm not entirely sure how CF multi-platform support will manifest itself in the retail consumer market, but it's for sure paying benefits behind the scenes, and contributing to the success of the company. I realize Centrafuse isn't everyone's first choice in front ends. But for a lot of folks who are perhaps intimidated by RR's steep learning curve, or aren't comfortable with OpenMobile's beta (alpha?) status, it's a great starting point. And as most of us have discovered, like all good hobbies, once you get involved it's hard to stop. You tend to try on different front-ends until you find the one that fits. At one point or another, I've had RR, OM and a couple of others (including one I wrote myself) in the car. For a number of reasons, CF proved to be the best "fit", but that's just me.
Anyway, development continues, progress is made and the future holds promise!