The channel selection v. Freeview is slightly different. Easiest way is to look in Radio Times (or similar) where the channel numbers for each station are listed. Look at the channels you're interested in watching and check where they are available.
I think one advantage of Freesat is that you will be able to get local programmes from other regions; local news and weather from another area can sometimes be useful.
It sounds a lot more Guilbert, but you get about 10 BBC regions, the same for ITV etc, so the difference isn't as big as it looks. For our taste the Freeview channels available that aren't available on Freesat are more useful to us; hence my recommendation that AOG looks up the channels before he chooses.