It is an difference if you play against forwards like Rooney,Ronaldo or van Nistelrooy or if you play against forwards who arent's so good.
Than it's easier for you as goalkeeper but it doesn't help you really to improve.
But some good Games is easy, but the International experience is important and from one or two games international you don´t get lot of experience and in the third league also.
Many International Games or games in the first league are important for the experience.
The best thing for Bayern is when Rensing play for one year in a other first leage club or so, like Phillip Lahm for some years