I dont find it hard at all, but then mine aren't high energy herding breeds. But many MANY people on our deaf dog yahoo group have 2 or more deafies. (they're addictive) And none of them find it tough. When I had the foster deaf Border collie, he was no different than having a hearing one, I would suppose, except for keeping him on a long line when on walks.
Go for it!!! There aren't enough people that'll adopt deafies, and there's even fewer that'll treat them like normal dogs!