I voted others. It really depend on the processing workflow if you are a photographer.
If you're using for leisure purposes, i believe any of them would make a good image viewer, even the Default Windows Photo App. serves you good too.
Yes I currently use Adobe CC 2015 - Photoshop, Illustrator, After Effects, Media Encoder, Dreamweaver, and Lightroom. LoL but those are all for editing not necessarily for viewing images a massive waste if you just want to view the image. That's why Faststone is a better "image viewer" than the others. But totally agree about the usage requirements. Though I would say about the color managers: that in some cases its not necessarily the image viewer color profile but the monitor color config profile. Though you are right the image viewer in win10 doesn't have a color config manager. I've run into the color issue every time I buy a new monitor regardless of brand Samsung has some nice color configs that are preinstalled but aside from that they all usually come without true color configs.. Thank god for the people that spend 5 hours messing with the config and making it perfect and posting them lol