I read Courant/John and thought it was very good, very well motivated and explained. I do not think it is obsolete, people still read textbooks from 50 years ago, just think of Herstein. Also, Courant/John has nice applications, and remember, when you get to university, you will probably do a physics course too, where Courant and John will be handy.
I'm not sure if the differences in rigour between the books is as big a deal as people make it out to be. I mean, after all, you will study Rudin's PMA or some equivalent book later, right? And that's uber-rigorous.
Oh, as for the problems in Courant and John, there are plenty. None are plug-and-chug. Many challenge you to think harder. But, I have not read either Apostol or Spivak, so I can't compare.