The best replacement for ghostscript is mupdf.

The best alternatives to ghostscript are rated as following:
★★★★★  mupdf
★★★★  postscript
★★★  pdftk
★  ghostscript lite

Your alternative for ghostscript is not listed? Suggest!
Speaking about ghostscript, one probably shouldn't forget about gimp.

Other search terms related to ghostscript and their ratings are:
★★★★★ gimp
★★★★ inkscape
★★ cups
★ imagemagick
You have in mind a companion for ghostscript and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ghostscript in all years. Click on graph for more.
ghostscript
mupdf
postscript