Schirmer editions are great, if you know what you have in your hands.
Without stirring the urtext myth, old Schirmer editions are notable for having editorial enhancements, which (in great advantage when compared with the more hypocritical recent editions by the likes of Peters and Henle) clearly indicate are not original to the text. I for one adore having notes of Hans von Bulow available to me when studying a Beethoven sonata, or Kullak when going through a concerto. The one studied with Liszt, the other with Czerny, both of whom were much closer to Beethoven than I am in about every respect.
More recent Schirmer editions are either excellent highly-edited books (like Tony Newman's edition of the Well-tempered Clavier) or very good "urtext" editions (like their Scriabin). Some excellent XX and XXI century music is only available from Schirmer, like the Corigliano concerto and the two fantasias.
That being said, I agree an old Schirmer book should not be your primary or your first edition for things like the Beethoven sonatas, Bach, Mozart, etc. But then, why on earth would you buy such thing with so much of it being available for free online at places like IMPLS?
If you like bound books, consider always Dover, which generally has good reprints (not always, but mostly). And you have to get over this fetish of having fingerings pre-provided in your score. Fingering is an act of decision-making regarding technique. It will serve you well to do your own, and if you can't then you do need your teacher to give you the principles that will enable you to do so, no matter how young or inexperienced you are.
Best wishes,
IU