I've been with directv for just over a year now and we subsribe to their HD service as well as an international package. This means that we have two huge satellite dishes that are installed in the back of the house. For the most part, I can say that the dishes have been reliable: there was one occasion where the internation Dish blew out a LNB and we needed to call someone out, but it didn't cost us any money. The other dish has been fine thus far.
Signal wise, the international dish has never lost a signal and is always available to watch no matter what the weather (I do live in socal so weather is not much of an issue). However, for some of the high def channels, it does give me an error such as "searching for signal" and I have to glitch my way on to watch it. I believe this is an error with the dish or the receiver and directv has no idea why it happens to me. Besides this minor inconvenience, the satellite dishes are okay and work relatively well. The size may be a problem to some because if you don't hide it, it may look ugly on a smaller house.