Twice as many threads. Whether that will benefit you depends on what you use the computer for, for just browsing the web or using light programs it would be pointless. Newer cpu heavy games are starting to make use of the extra threads on an i7, which will make a difference assuming you have a powerful gpu and a high refresh rate monitor. For say rendering and other workstation tasks an i7 can also help a lot.
Personally I wouldn't recommend an i5 at all, the ryzen R5 1600 is better value than any i5 in my opinion.