I would probably go with beta alanine because you can eat some good carbs in oatmeal after a workout, and the tingling feeling for beta alanine is :woohoo:
I just eat oat meal or a whole grain cereal after working out and it seems to do quite well for me. I will be trying a carb supp soon though, but I can't give any feedback on that yet...
if you can't get those carbs in post workout, then I would think WMS would be more beneficial, because what you eat is most important.