It's important to note for those who do not know, the body processes glucose and fructose differently. Here's a great lecture on that subject, describing how dangerous excessive fructose consumption could potentially be.
In my mind, brown or white rice syrup equally stand as the top sweetner for those that wish to use a sweetner. Obviously they are not paleo nor are they necessary, but I think they are the least problematic sweetner since it is basically a dextrose syrup. Dextrose is just glucose-glucose disaccharides. From what I understand, the rice used to make rice syrup is not GMO which is why I've seen an argument preferring rice syrup to plain corn syrup, which also was a dextrose syrup but is made mostly from GMO Corn. I think it is important to view sweetners as something to be consumed in extremely limited quantities as too much of anything sweet should still trigger the chemical reward pathways related to sweet tastes, which operate similar to the heroin reward response in the body (as discussed in David Kessler's great book "The End of Overeating"). In addition for people with comprimised metabolisms or diabetes, you'd want them to stay miles away from a glucose syrup. For those with healthy metabolisms and who need a sweet fix occasionally in my mind it would definitely be preferable to pretty much all other sweetners which usually have nearly half fructose at minimum: regular sugar (sucrose - glucose-fructose dissaccharide), honey (about 50.5 percent fructose), maple syrup (95 percent sucrose, 1 percent fructose, and 3 percent glucose), or agave nectar (aka hippie high fructose corn syrup - produced the same way and higher fructose than HFCS).