Fagrifoss on Kaldakvísl is for sure much more popular among fisherman than among tourists. The area nor the views are anyhow spectacular (in the realm of Iceland) and in any case you should confuse this waterfall with an another icelandic waterfall of the same name Fagrifoss in south east highlands.
How to find Fagrioss:
Fagrifoss on Kaldakvísl flows near the road F26. Turn here (GPS: 64.300479, -18.980435) to the west and drive for about 2 kilometers.
GPS coordinates of the Fagrioss waterfall: 64.301928, -19.025636 Take me there!