These speakers are very convenient and easy to use. They work throughout our 3-bed house and garden, saving me wiring up the kitchen for sound and providing audio from the media PC during DIY/gardening/cooking. The docs said they need a minimum of 7 metres from transmitter to speaker, but I haven't found this to be a problem. 2m is fine. With the addition of 6AA batteries (Uniross 2700mah, lasted a few hours), they did a grand job for our pub quiz's music round.
Almost no set up is required - besides putting the slightly weird-shaped power adapters together, which convert from a European-style plug to a UK one. These adapters stick out a long way, but do the job and could no doubt be replaced if they didn't fit where you wanted to use them.
It's worth noting that the 4 buttons on top (Power, Auto Tune, Volume Up Volume Down) are electronic, not physical. That means they won't remember your volume setting from last time they were on. You'll probably want to turn them off when not in use as they can make occasional "fzzt" noises when there's no signal. You also need to turn them on with the button each time the power is restored; hiding them on top of a high shelf or cupboard and only turning on/off at the wall wouldn't work.
Power consumption (YMMV, these are what I've recorded at the wall socket):
Per Speaker, idle: 4W
Per Speaker, full volume: 5W
Base unit, idle: 3W (dropping to 0W
Base unit, transmitting: 3W
I'm no audio buff, but I'd describe the sound quality as good for what they are. They're wireless speakers about 21cm high the speaker cone is less than 10cm across, so don't expect faithful reproduction of your 320 Mbps MP3s. They're certainly better than even a modern portable radio and more than adequate for speech or background music. As the speaker cone faces downwards, sound quality and volume is better if placed on a large flat surface like a table or tiled floor, without too much stuff crammed around it. Putting them on carpet or grass and it goes a little quieter.