Sliding sash windows look great, they are usually in the older houses - like mine. However they do give allsorts of problems in the older houses. Most sash windows are not double glazed, and that is hell for the bills and keeping the heat in the house during the winter - even here in Ireland, where it is never really cold.
I knew all this before moving into this house, so why did I go for something that was going to cost me much more money in the long run? Well, firstly - they look great. And they are usually much bigger windows, letting more light into the rooms - which makes a great difference when one spends so much time at home sitting in front of a computer as I do.
However since moving in the windows have slipped somewhat and will not go back again - and have ever tried getting an Irish landlord to fix anything. They have all read Castle Rackrent I guess.
So the next house will be more utilitarian - double glazing please.