I wanted to add onto this. I'd consider checking out AMD processors since Intel's chips have been found to have some pretty big security flaws in them. These issues have been baked into the parts of the hardware that are meant to improve performance. OS-level fixes will leave the system in a pretty slow state if you apply any.
However, if you aren't worried about that, then yeah, an i5 would be way better than an i3. I got an i7 about a year before the security stuff came out. While that does concern me, the performance has been quite nice. If you're doing a lot of audio rendering or using a bunch of fancy softsynths, it would be worth considering getting a higher-end processor.