CNET has reviewed a mini PC from Polywell, here's a short snip from their full evaluation:

You can take a number of paths when jumping into the world of Media Center PCs. You could pair component-style box with your A/V receiver, or if your home-theater cabinet is full, you could stick a traditional desktop chassis in a closet or an office and access its contents via a Media Center extender. There's also the option of a small-form-factor (SFF) case, which you can hide (or display proudly) among your living-room components. We've seen SFF Media Center PCs from Shuttle and Polywell that have attempted--with mixed results--to squeeze a fully functional Media Center PC into a tiny case..



Link: CNET