Pentax is moving backwards when the rest of the digital SLR kingdom is going forward.
The newest version of Pentax mid-level DSLR is the K-5; the older version is the Pentax K-7.
It doesn't make sense.
Why isn't it a higher number than the previous one? Go figure.
More important than the name are the upgrades.
Is this new camera worth your attention? And, by the way, which one has the higher user rating? More on that later.
Pentax is saying that the K-5 is a "refinement" of the K-7.
We generally think in terms of upgrade.
Another Pentax anomaly.
Whatever.
The upgrades...
ok, refinements, are in some expected areas.

1. First, the CMOS sensor has increased from 14.
   6-megapixels to 16.
   3-megapixels.
   
2. There is an increase in the continuous shooting rate from 5.
   2 frames per second to 7 frames per second.
   
3. ISO has been refined to go all the way up to 51,200 instead of a paltry 6400.
   
4. There has also been an increase from the 12-bit RAW bit depth to 14-bit.
   
5. Video recording has also been improved to full 1920x1080p at 25 fps rather than 1536x1024p (they were the only ones with that size video which was rather unusual).
   

Many cameras are including in-camera HDR now.
But the Pentax people have somehow added automatic image alignment so that you can shoot while hand-holding your camera.
There are other benefits that are common to both cameras that are well worth mentioning.

• Having a camera that is weather resistant is important when you are out in the elements.
  The Pentax models both sport a magnesium alloy body over a stainless steel frame, and they are weather-sealed for that necessary protection.
  So go ahead and jump into the snow or surf with either.
  
• Another great feature of Pentax DSLRs is the image stabilization that is built into the body rather than being dependent upon the lens IS.
  
• Also, every lens made for a Pentax SLR is compatible with the newest models.
  This is a huge advantage for those who are old Pentax owners.
  

The Pentax folks have not entered into the advertising wars to promote their cameras.
Instead they depend on quality and user satisfaction for product promotion.