I just asked the same thing not too long ago about the K10D and GX-10. Here's my take. Nikon and Canon are everywhere. Pentax is a great system offering great value compared to Nikon and Canon but not as many people know it. Samsung is simply a rebranded Pentax and even fewer people know it. That means that it's more likely that you can get K20D functionality with a Samsung label at a discount because people simply don't know. If you watch eBay for a couple of weeks, the Samsung prices are generally lower.
I went with the GX-10 for that very reason and was able to get the functionality I wanted at a discount.
The only problem is explaining to the Nikon and Canon crowd the value proposition of the Samsung label!