I think I can say that every club in Italy would like to have Ronaldo. He's gotten a bit older, but he's still very good. I do not know what the relationship is between Ronaldo and the management of the club at Juventus. I think he still has a good relationship with the players. If a club like AS Roma gets Ronaldo, that will of course change the title chances for this club, let alone what happens to the chances for Inter Miklan if he went there or Napoli.
The rumor regarding his price is 12m/€ before taxes so there are not so many clubs who can pay so much.
Also, he wants probably to play in the champions league so if he comes back to Italy it can be only Juventus or Milan.
Inter have a problem with money right now I can't see them depending so much.
For Cristiano Ronaldo, I think Juventus is the best option. And after that comes Milan. Inter is probably not going to be interested because they have their own problems with the financial situation going on right now.
But I really highly doubt that Cristiano Ronaldo is going to be back in the Italian league. The last I heard was that he was thinking about staying in Manchester United. So, in that comparison I think going to Juventus or Milan should be considered a good move. First of all, he will be able to play in the champions league, and secondly, I think he will have better support from his team.