As a casual observer, my impression is that multi-core processing needs more software optimization. Out of the box, higher clock speeds would be noticeably faster on many accounts. However, modern CPUs are very complex. E.g., clock speeds and individual cores could be throttled depending on the situation and never reach the marketed upper limits and efficiencies. That is why there are benchmarks. Even then those are idealized tests.
Personally, I would to reserve some of the budget for more RAM than I think I would need. I often find that RAM is the limiting factor to my (low-end) system.