It depends on what part of Argentina, Buenos Aires and Rioplatense accent use a strong rolled R, meanwhile in Cuyo region (center-western: Mendoza, San Juan, San Luis and La Rioja) it's pretty common a very different sound for the R, that's closer to an English 'sh' sound. I believe it is being lost though and younger people use the rolled R but not as strong as in Buenos Aires. There a lot more differences with the Rioplatense accent, like with the Y and LL. Accent from Mendoza and San Juan are much closer to Chile's than to Buenos Aires accent.