There are reviews all over the web, so I'm a little puzzled as to why you are here. But you are so...
It's a fine camera, but I don't know why you'd want to jump ship. Yes all alphas can shoot in manual mode, aperture priority etc, but if you have invested in pentax glass, why not keep it and get a pentax dSLR? If you don't have a lot of money invested in the Pentax system, then I guess jumping to Sony isn't such a big deal.
Keep the megapixel count out of your head, it doesn't matter. dSLRs have giant image sensors that are better than compact cameras by a long shot. Also, get it out of your head that there is such a thing as a good or bad camera for an amateur. It's like saying there is such a thing as a good or bad car for a beginner driver.
If you plan on going Sony/Minolta alpha go here http://www.dyxum.com/dforum/forums.html
spend time lurking, reading and search for your answers/questions don't start asking questions right off the bat, it annoys everyone. And by the way, in case you want to cut your teeth on something cheaper, check out the slightly older Sony Alpha A200, or the model below the 330, the A230.