Hi Candy,
We use the Vicks brand - it's the one with 2 tanks and it heats up the water for warm mist. It is a bit large, but all three bedrooms are across from each other and if we put it in the hall, it gets all the rooms, so it works REALLY well! It does have a bright blue light, but we just put a stickie note over it and it's fine. The only thing is, I didn't know I'd end up worrying all night about the hot water. I worried that if I left it in with the kids, they would somehow knock it over in the night if they got up and get burned. We ended up sleeping in the living room with it down the hall. Something to think about warm vs. cool mist. Usually the cool mist is recommended just for this reason, but I was told by our pedi. that they work the same. Other than that I really like the brand and we've had no issues. It's easy to clean, just dump out the tanks and let air dry. There's also a little "cup" on top so you can add a vaporizing liquid, like Vicks, if you desire. We bought it at Babies R Us, but I can't recall the cost. Good luck! - Kim