I think what you are looking for is how to determine how well your model is performing.
The best way to do this is to define a set of testing data to compare your model's performance. When I was working on different models, I segmented my data into three pieces: training, validation, and testing. I used the training and validation as part of the training process. I then used the testing data set to test and compare the results of each model. Since the validation data is not used for training, you could also use the validation set as the testing set to get the actual performance. What you don't want to use is the training data (since that is data that is being used to adjust the weights in the model).
I don't think the final loss values or the final predictions were very useful since that is just the output from the latest iteration of testing (I don't think they are cumulative across the training process).
Patrick