[Altimas]

MR>*
AWD helps you get the power down but seeing as most AWD setups are front engined, you get similar weight distros to FWD cars so you get arund 60% weight in the front generally so it doesn't handle any better when not accerating (worse than FWD since it adds weight) but it helps you get out of the corner.
Given alot of AWD setups are FWD untill the front wheels slip(vicous coupling) and then use a 50:50 spit (based on FWD) I really wouldn't touch those with a 10 foot pole since they have power on understeer.
But with cars like the wrx with adjustable splits, it's better since you can make them behave like a RWD car but still fat slicks AWD isn't needed for tarmac racing.
Basically AWD doesn't help handling a bit, it just helps you get the power down while MR and argubabally RR help handling and getting the grip down.
The problem with MR and RR (more drastic) is lift off oversteer and with RR (porche's) is power on understeer since there is so little weight up front.
RR is excellent for braking though.