I buy whichever looks the leanest. i never soak it. Although you may have read my answers praising my slow cooker as i cook all my meat in there, this is one thing that cooks better when boiled in a large saucepan (I actually use my 30 year old pressure cooker, not under pressure but i find the lid locks on and cooks it extremely well). I bring it to the boil (with cold water) then tip the water away and start with either fresh water or diet coke, yes you did read correctly!, cook for amount of time appropriate for size of joint then leave it to cool completely without removing the lid - unless we want to eat it hot of course. After much experimenting my family always passes best comments when i cook in this way.