The best replacement for nestopia is jnes.

The best alternatives to nestopia are rated as following:
★★★★★  jnes
★★★★  rocknes
★★★★  fceux
★★  nintendulator
★  nesticle
  mednafen

Your alternative for nestopia is not listed? Suggest!
Speaking about nestopia, one probably shouldn't forget about usb controller.

Other search terms related to nestopia and their ratings are:
★★★★★ usb controller
★★★★ xbox controller
netplay
You have in mind a companion for nestopia and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of nestopia in all years. Click on graph for more.
nestopia
jnes
rocknes