you can easily use the stand alone facerig with the advanced biped, you won't face any problems (pun intended), is was made for that purpose.
although the toon rig is made for toon characters, it also can handle realistic characters, you just then don't use any of the stretchy/bendy features.
so what you decide to use mainly comes down to your personal preferences. feature wise the face rigs are more or less on par, there's slight differences in functionality and setup though...
there are examples in the content browser for the toon rig and the face rig, just give them a spin and see which one you like better.
the body rig of the toon rig preset has a bit more features than the advanced biped, apart from the squetchy and bendy features there are a couple of handy space switches and some other things the advanced biped doesn't have. for instance the hand gizmo makes it very fast and comfortable to get nice finger poses with a single controller. also it's a little bit faster than the advanced biped.
those are all the major differences i can think of, both are good stable rigs. again, in the end it comes down to personal preferences.