In one aspect, a composition for treating fibers comprises an acidic aqueous or aqueous-based continuous phase and a liquid repellent phase comprising a dendrimer component and/or non-dendrimer alkyl urethane. The treatment composition, for example, can have pH of 2.5 to 6.5. In some embodiments, carboxylic acid is employed in the treatment composition for providing the acidic character of the aqueous or aqueous-based continuous phase. Moreover, the treatment composition can further comprise at least one of an acid stain resist component and soil release component. In some embodiments, fibers treated with compositions described herein exhibit ionic character.