This paper presents the evaluation of the analog properties of nMOS junctionless (JL) multigate transistors, comparing their performance with those exhibited by inversion-mode (IM) trigate devices of similar dimensions. The study has been performed for devices operating in saturation as single-transistor amplifiers, and we have considered the dependence of the analog properties on fin width W-fin and temperature T. Furthermore, this paper aims at providing a physical insight into the analog parameters of JL transistors. For that, in addition to device characterization, 3-D device simulations were performed. It is shown that, depending on gate voltage, JL devices can present both larger Early voltage V-EA and larger intrinsic voltage gain A(V) than IM devices of similar dimensions. In addition, V-EA and A(V) are always improved in JL devices when the temperature is increased, whereas they present a maximum value around room temperature for IM transistors.