I own 3 of these. They're pretty much the cheapest option you can have for RGB wireless lighting, of course with some pretty hefty consequences. The app is just barely laggy enough to be irritating, connecting to the bulbs always takes a while, sometimes they randomly disconnect or don't show up, and the interface for controlling the colors is horrible.
Something to be wary of is that the white light is much brighter than the colored lights, and they vary in brightness. I have a moderate-sized apartment (30m2), and three bulbs. On white, without any other lighting, I'd describe the lighting as slightly dim. On blue, the room is quite dark with hints of blue light. With pink/red/green, the room is slightly less dark but still dark.
Each bulb can light a space about three square meters well; my bathroom is slightly bigger than this. I put one bulb in it and on white mode it is lit well. On color mode, of course, it is dim, but right on the border of acceptable.
The physical hardware product is very nicely designed and looks beautiful, to the extent that you might actually prefer exposed bulb lamps/fixtures.
Although it doesn't really make sense to me, I've bought more, due to arrive tomorrow. They're cheap enough, semi-hackable, look nice, and if you buy enough you can overcome the dimness problem.
They're far cheaper elsewhere though, check eBay.
Feel free to ask me anything about them.