I installed this weekend W7 RC. A clean install in my 15 Gb test partition and ending with around 5 Gb free. In 2 hours I was answering emails and working. Even when Fujitsu has not released any drivers for W7 for the P1610 series, more or less I have everything working (the screen does not rotate automatically when I rotate the display to tablet mode).
I'm really happy with this release. It seems strong, well made. It seems a product ready to hit the market so I would not be surprised if I see it released in this Summer.