I bought a set for a small flat in France where I wanted to relay satelite from a bedroom (where the dish is) 10 metres through a stud wall and a brick fireplace to the lounge area where a flat screen TV is. The satelite signal's pretty strong.
It's easy to set up and get working, and the infrared sender seems good, but I've never got a great picture, and occasionally it's a really bad picture (black and white, occasionally get the bottom of the picture at the top) - I can cope with it until I can be bothered to run wire through the place, but as reported by others, people walking between the two units can affect the picture, as can wifi (causes slight strobing regardless of channel selected), baby monitor and portable telephones (these last two not so much though). Curiously, the picture seems at it's worst when it's graphics (e.g. satelite menu screen, screen overlay on a phone-in, that sort of thing) but it may be the TV (28 inch Phillips flatscreen) trying to compensate (the TV apparently has this feature, but I haven't tried switching it off yet)
To be frank, if I was in the UK I'd return it as not fit for purpose, but I'm still in France so it's more hassle than it's worth. Oh well, caveat emptor.