do you use both? If yes,
I'm curious what you'd use each one for - when or why you would choose to open one instead of the other?
I use Irfanview, if the images are not too big ( i mean in length ),for faster viewing of images and if the images contain large information and needs a magnifier and for short editing Faststone is the default choice for me, i tried Ashampoo Photo commander, to view 15 jpg images named serially from 1-15 and guess what, after reaching #4 i try to view the next image , it would jump to image #7 its all haphazard, tried it with even Ashampoo Photo v.10, just for a photo editing and viewing its bloated.
Their are few things which is good like batch renaming short editing, with little better aesthetic feel etc but little more bloated. I don't have it anymore.
Faststone never shown this bug, its stable as bedrock. Batch renaming works beautifully, croping and texting an image work fine,,,ideal choice for viewing digital comics.