What should you look for in a camera? How long is a piece of string?
First, even a cheap camera can produce reasonable footage if you learn what you are doing. Local theater groups are a good place to volunteer as a lighting stagehand. Bad and insufficient lighting can make a great camera give poor results, so it is important to learn how to light your scene.
As for a camera, it is good to stress test the camera in store if you can, and preview the footage in store on a computer if you are allowed to. Record in very dark areas and look for grain (random speckles) in the darkest areas of the recording. Check the focus quality at different distances (try for the distances you intend shooting at). Can you switch off automatic features? You do not want auto focus or auto white balance giving you trouble mid scene. If you can, try to shoot in HD 16:9 and without pulldown. HD may not be standard yet in many European countries, but it is standard in Japan, USA, almost standard in Australia, New Zealand, UK, and many other countries. I have had trouble with interlacing and pulldown for decades. It can slow down many edits and effects. Though at your price point you will probably have to live with pulldown (thankfully it is not as bad as interlacing). You may want to check daylight performance. Look for white blowout (pale colours all flooding with white unnaturally). When you hit 100% white with most cheap cameras, you can not recover any detail or colour from the area in software.
There is not a lot of difference between Mini DV, SD, and HDD recording. From my own experience and from friends and colleagues who did not listen to my advice, Sony are cheaper to purchase feature for feature, but they charge a lot more for media and replacement batteries. I personally will never touch another Sony product. I was burned a long time ago when Sony were restricting the availability of Memory Sticks. Had to cancel the whole shoot after a fruitless week of trying to source memory sticks on set. Funny because we were only minutes drive from one of the largest tourist traps in the world where one would expect camera media to be available.
At your price point you will probably have to do without 3 CCDs, so look for a larger single CCD if you can. Again, see if you can record some footage and check it on a computer (the 2.5 inch screens on the cameras are useless for checking your footage) to be sure.
There are many things to check. You may need a robust camera, you may be able to get away with a cheap flimsy camera. It all depends on what you will be using it for, and who will be using it. You may need a camera that can be run non stop on one battery for five hours? Without knowing more about what you want to use it for, the best anyone can do is give you general advice and hope it is good enough.
Oh, and audio. It is important to have headphone socket to monitor your audio. That can ruin a days worth of shooting if you are unaware of audio problems. A microphone in jack would be good as well, and an XLR (Balanced Audio) socket is far better than an audio jack (though not necessary if you are shooting a horror flick in a forest if you are not close to lighting). Balanced audio removes magnetic field hums that studio equipment gives off.
Good luck.