If you want to look at the information direct from the NWS, go to Model Analyses and Forecasts
Generally speaking, the NAM model is a bit more precise as it's a higher resolution model than GFS. This is, of course, just a general rule of thumb. GFS can be used to give you an idea of longer term forecasts but I wouldn't use it for short term. Because of the higher resolution, the NAM model generally does better predicting precipitation and its effect on atmospheric destabilization. This destabilization is what then translates into wind speed and direction and would explain why you are seeing some of the differences.
Since you are looking at Sunday, I would probably say that the GFS forecast might be more indicative of what you will be seeing, but if there's any precipitation involved neither model is going to be overly accurate. That far out the weather is pretty much a crapshoot - especially these days. GFS tends to have fronts moving at a higher speed than what actually happens (not sure why, but these models are all computer generated so I'm sure it's algorithmic), so once again - Sunday is a long time out for any modeled forecast.