I have two common scenarios:
1) I am adding a new food to my diary and have to figure out which database entry has the most complete and accurate nutritional data.
2) I am trying to decide what to eat between a few options and trying to figure out which one is the best choice nutritionally.
In either case, it would be very useful to be able to do side by side comparisons of foods. That way I can make sure I'm getting the database entries that have data on all the nutrients of interest to me. Many times I only realize after a long time of using a particular entry that it is completely missing in potassium, magnesium, or the amino acid profile for its primary protein source(s). That way I can also choose foods based on which one complements my nutritional needs for the day. Oh wow, I could eat THAT but THIS would be the better choice given my current nutrient ratios for today.
The oracle is really nice, but I'm surprised it doesn't allow for direct comparisons.
As a last note, it'd be really nice to be able to search with more granularity. Like which foods database, or search and sort based on number of nutrients accounted for or by amounts of this or that nutrient.