What to buy and why: Entry-level mirrorless cameras

Basically, if you can’t make great photographs with any of these cameras, is is not the fault of the camera. There are, however, certain advantages to the Pentax K3, which I find compelling:
* it just feels great in your hand – elegant and ergonomic
* the lenses, particularly the limiteds, are rugged and indisputably top-of-the-line
* the K3 body may be slightly heavier than some, but remember, is it waterproof (well, protected) and rugged; furthermore, the compact and lighter lenses compensate for the body
* the lenses tend to be much smaller than those of other makers, so if a light and unobtrusive package is of value to you, advantage Pentax
* the weatherproofing is superb, and note that many of the lenses are equally weatherproof
There is likely no reason to switch to a Pentax if you are happy with what you already have. But if you are starting out or are simply fed up with the huge, bulky DSLRs with gigantic lenses, I would highly recommend a Pentax K3.

Source Article from http://www.dpreview.com/articles/4259691750/