Is sugar more filling than HFCS?

No.[1][2][3][4][5]

No differences in leptin or satiety have been found between the two.

References

2.^Monsivais P, Perrigue MM, Drewnowski ASugars and satiety: does the type of sweetener make a differenceAm J Clin Nutr.(2007 Jul)
4.^Melanson KJ, Angelopoulos TJ, Nguyen V, Zukley L, Lowndes J, Rippe JMHigh-fructose corn syrup, energy intake, and appetite regulationAm J Clin Nutr.(2008 Dec)