In my experience, yes in the past Telefonica have been pretty rubbish but over the past couple of years I think they have improved considerably.
I haven't had any problems with new lines, connections, etc, with them recently and I am much happier with them than I used to be.
I can't speak for other companies but I, personally, have found Telefonica to be just fine.
I think they need to start paying me some money for saying some nice things about them....I'm sure they are not used to it
Justin