Both CPU's offer similar performance, the differences between them are not significant because the i5 albeit low energy has a frequency of up to 2.6GHz turbo in one of their nuclei, whereas the i3 works with its two cores to 2.4Ghz. In practice this is probably the minimum for i3 but in any case negligible difference.
Both are fourth-generation CPU's so the differences between both optimization or efficiency due to generational changes are negligible. In addition the graphical i3 has a slight advantage with HD4600 HD4400 400MHz 200MHz against i5. Finally it should be noted that the i3 can be updated by a superior CPU if necessary and instead i5 can not be replaced because it is integrated into the motherboard.
The advantage of i5 As I have already mentioned is the consumption which has a maximum TPD regarding 15W 37W i3.
If we put everything on the scale choice depends on what you're going to make the team, if such premium autonomy, the i5 would be ideal, however if raw performance or other factors as a possible upgrade in the future, then the i3.