Hans, has some great points. I'd also like to add another consideration. Type of battery. The Pentax has a Lipo battery, which is nice most of the time, except for when it dies and you would like to throw some AA's in and can't. So I also recommend that you consider that. Nothing like being half way through a hike and having your battery die, and unable to replace the battery.

For high quality Macros I steal my wife's Canon Rebel xTI, and her macro lens.

Paul