For me, Freesat wins hands down over its rivals; Freeview and Sky.
Admittedly, FreeView is easy to install, you simply buy a box and plug it in, don't you? Yes providing you get a good signal through your aerial. If you don't get a strong signal then you will have viewing problems, pixilation, channels disappearing (regular retuning needed) etc. That's why it's earned the nickname FreeView figital TV.
Rather than having a new aerial installed to receive FreeView, I would rather get a dish and receive Freesat with its much greater choice of programmes. One thing to note though, some Freeview channels are not currently available on Freesat. However, on demand TV will be available to Freesat viewers via iPlayer and ITV Player with Channel 4 and 5 probably joining them so, another plus point to Freesat.
Complete Freesat systems are available for under £50. Unless you are handy with power tools and ladders, you will need someone to install the dish for you, about £50, I installed my own, it wasn't rocket science.
Installing Freeview would cost about the same with a new aerial and box, but you get a lot less channels to view.
So, with Freesat you get a heck of a lot for FREE, with Sky you get a heck a of a lot of adverts and repeats for which you get the privilege of paying a monthly fee plus additional payments for premium viewing. I know which I prefer!