Kaiser, I've got one, my house had a condesation problem as the previous owners were Greek and blocked up all the vents to keep the Scottish weather outside.
Absolutely amazing how much water can be extracted from the air, we got 6litres or more per week.
Also good for drying your clothes indoors if placed close as they suck the moist air from around the clothes.
Could have done with it in my garage as the humidity in mid winter got so bad that wooden stuff swelled up and some metal rusted.
Only issue I would have is the cost of running it in these hard financial times.
Cheap alternative is salt traps, dishes of salt placed around the place to attract and absorb moisture. No where near as good though !