XnView is a good alternative to IrFanView and the two programs are usually toe-to-toe in the quest for useable features and the race of keeping a trim codebase at the same time.
After getting tired of AcdSee Classic - it didn't have *any* unicode support - I looked for an alternative. AcdSee has become bloatware. Hence I needed something else.
I found XnView and IrFanView the best for my practices. I read manga as well as comics on my PC, so needed something more flexible than a bare-bones viewer, but it also needed to be more streamlined than an editor.
I finally settled on XnView as I could configure it to reproduce all my AcdSee ingrained key-commands and behavior. I say, try both, one may be to your liking.