The best replacement for firestorm is bersa.

The best alternatives to firestorm are rated as following:
★★★★★  bersa
★★★★  captain atom
★★★★  human torch
★★★★  singularity
★★★  storm call
★★★  second life viewer
★★★  fireball
★★  fireball poe
★★  thunder
★★  fury 2
★★  sl viewer
★★  rustler
★  god's wrath
★  ryobi
★  firelord
★  gods wrath
★  chaos storm
★  traxxas rustler
★  rage of god
  armscor
  mt2
  bersa 380
  fire tempest
  quasar
  jato

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

Other search terms related to firestorm and their ratings are:
★★★★★ rlv
★★★ opensim
You have in mind a companion for firestorm and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of firestorm in all years. Click on graph for more.
firestorm
bersa
captain atom