It really depends on what is required in your contract. For example, if you are using Revit to calculate concrete volume then you need to use the 3D rebar tools. In live sections and drafting views I found that the detail families for rebar work nicely and they give an accurate representation of the rebar size. I only use the model rebar elements if I am required to by a LOD spec or if large rebar ( >#7) is used and I want to make sure everything will fit with accurate bends and sizes and spacing. For typical reinforcement in slabs and footings with less than #7 rebar I just use linework but detail rebar families look better and you can accurately position rebar to the edge of the bar. Linework is faster.
