I haven't taught in a while, and my teaching credentials pale in comparison to others. That being said, I end up using Simandl fingerings quite a bit in the lower positions and for playing anything that is primarily pentatonic.
Ed Friedland's Hal Leonard Bass Method book 1 recommends a index-middle-pinky over three frets/stops that is similar to Simandl.
Also, a dude from Berklee with whom I took two lessons at one point recommended the Simandl book.
I've also had Evloving Bassist by Rufus Reid (a Jazz Double Bass book) recommended to me for bass guitar, which advocates a similar approach to Simandl but uses a lot more shifts.
OTOH, the American School of Double Bass recommends a hybrid Simandl/finger-per-"fret" approach that they call Simandl-plus (
http://www.asodb.com/sp/sp2.html), however, Double Bass pedagogy is, admittedly, waaay out of my league.