Help and information on external wall insulation

Would like so opinion on if pros and con regarding external insulation is it any good have been told that I too could get a government grant to have this process to my home but hesitate in at present see below
The house next to me is owned by the council, its the only one in a row of terrace houses the blocks have been put over my boundary line and am not happy but need to know if this will make any problems when my children sell at later date