One of the drawbacks with R has been its limitation with big datasets. It stores everything in RAM so once you have more than 100K records your PC really starts to slow down. However, since AWS allows you to use any size machine, you could now consider using R for scoring out your models on larger datasets. Just fire up a meaty EC2 with the RStudio amazon machine image (AMI) and off you go.
With this in mind I wondered how long it would take to score up a Neural Net depending on how many variables were involved and how many records you need to score out. There was only one way to find out.