jlarocco laid out a few of the open source options (all of which are quite good at this stage), and when it comes to web mapping I would say ESRI is well matche

jlarocco laid out a few of the open source options (all of which are quite good at this stage), and when it comes to web mapping I would say ESRI is well matched by Mapbox, CARTO, etc. If you're looking for a specific non-ESRI tool, post about it and I'm sure you'll get some interesting feedback.