1) Order extra batteries, you will need them if shooting for more than a couple of hours.
2) Despite the small sensor, IQ is surprisingly good at the lower ISOs. The basic zoom lens is very sharp, even wide open. The photozone.com review is worth reading.
3) Depth of field could be an issue since the small sensor and lens combinations make a lot of the image sharp.
4) There is a benefit to the small camera: It doesn't get in the way. The IQ won't be as good as a DSLR, but it your goal is screen or 8' x 10"s, then this is just fine.
5) An interesting benefit to this camera is with telephoto photography (e.g., birding). The crop factor is 5.5, meaning you can stick a 300mm lens on it (with an adaptor) and get a 1650mm 35mm equivalent, or the sharp 50mm 1.7 Pentax M that everyone buys for $45 on ebay and get a 275mm 35mm equivalent! If you need quality images from a super telephoto, but don't have quality lenses with the 400mm+ reach, the Pentax Q offers a cheap and easy way to do this (provided you don't mind using cheaper older lenses that are manual). As most people know, you can get better image quality using a great 200mm lens (and blowing up the image) rather than using an average 400mm lens. Well, now you can use that super-sharp 100mm portrait lens gathering dust in the closet and get great images using it as a 550mm equivalent on the Pentax Q. This is an interesting benefit to the camera.
6) Shooting RAW is no problem on those HDR shots (assuming you do not want to use the in-camera HDR mode) by making a selection after the shot. I wish I could just set the camera to capture all shots in RAW automatically in certain situations.
7) Definately upgrade to the new firmware as soon as you get the camera. It will help with focusing and with other issues.
8) I am disappointed in the fish-eye, since it is more of a "toy" lens than a super sharp one. It is just fine when shoot something close to you, but the "distance" shots (like the inside of that romantic Irish Pub you crawled into) are just average.
9) The main knock on the camera was never the IQ, which is good emough. The issue was what you are getting for $800. Well, now the price is below $250 with the 02 basic zoom lens. I can easily justify the cost because: 1) It is so small I can always have a camera with me (like when skiing), 2) I now have an inexpensive way to shoot long distance shots with very good to excellent IQ; and 3) It is simply fun to use.