Funnily enough, I just briefly posted about SU holidays on another thread here.
My two boys have been going on them for years and I have nothing but praise for them.
My boys have done sailing, karting, multisports, dirt bikes, arts and crafts and many other activities over the years. The one both of them liked best was full of what I would call "fresh air" activities such as building dams, sleeping outdoors (supervised of course), camp fires, stream dipping etc...
We have always found they have a superb adult child ratio on all their holidays, the children always have a positive experience and the facilities are excellent.
My daughter isn't old enough for SU yet but has been on PGL and had a good time there.
Scripture Union are also fabulous value for money at around 1/5 of the price of PGL but the facilities are just as good. The boys have stayed in all sorts of venues - log cabins and private schools - the sailing holiday one they stayed on the boats.
As I said on the other thread too the confidence and independence gained from such experiences is invaluable. My children have friends all over the country and have many fantastic memories from their time away from mum and dad.
If anyone wants to PM me about SU holidays I'll be happy to answer any questions or chat more about them.