I tested this unit in my office/bedroom with a hygrometer (measures room humidity). My room is about 120sf (below the 150sf for which this unit was designed). Before starting the Honeywell Mistmate, I measured the humidity in the room at 38% with my hygrometer. I then started my ceiling fan, but in reverse so that it pulled the airflow upward (most ceiling fans have a reversing switch on the body of the unit). The reason I wanted to use with the ceiling fan was to pull the mist upward and then disburse in the room rather than have it fall too quickly. I also closed the bedroom door. After getting the ceiling fan running, I then started the Mistmate and ran on the highest setting. In less than an hour the humidity reading had climbed to 59% (and still climbing).
So, several lessons learned. The first is that the Honeywell does do an effective job raising the humidity level quickly in this size room. The next lesson is that it does have the ability to raise the humidity above a comfortable level depending on room size, and with door closed. So, if you buy one you will need to experiment with your own room. Also, be aware that you might want to reduce the dial setting at night so that the room humidity does not climb too high while you are sleeping. From what I have read, keeping the humidity around 50% is good. So run it on high to get to ideal humidity and then dial it back. Also keep in mind that having too high a humidity could cause mold growth.
The unit is very quiet with a slight hum and occasional bubbling sound. It is a nice size and shape. The unit will automatically shut off when out of water, which is nice. The .5 gallon reservoir is good size for filling and carrying. I like that the unit does not require a filter. Filters can get expensive.
One other tip: if you run on your desk, make sure the mist points away from the desk, otherwise the moisture will begin to soak into papers on your desk.
You might invest in a hygrometer. A good, but cheap one, can be had for less than $10.
The most important tip is to use the ceiling fan (but not blowing down, of course). Enjoy your Mistmate!