Because it is easy to eat a lot of calories of sugar alcohol's in a very short time period, I avoid eating them. Compared to dextrose, they are believed to have less insulin spiking ability. I think that some sugar alcohol's are believed to have no insulin spiking ability.
Generally, people feel that in small quantities sugar alcohol's will not cause much insulin release. The quantity problem arises often, as you mentioned your fav. bar has 19-25 of sugar alcohol's, which is in the range of 100 calories. Sugar alcohol's can be stored as fat like any other calories, so eating too much of them can have the same consequences of eating too many calories from carbs. Eating sugar alcohol's rather than dextrose may have some advantages, if they don't cause as much insulin release, you will probably remain full for a longer time.