I mean the domain you're in changes your requirements drastically. Heck certain workloads (high frequency, low latency, nearly no concurrency) might run better on a single core of an overclocked i7 vs any Xeon processor.

If it's a web server then obviously you want more cores, and an event driven server would make a lot of sense.

Basically if you need concurrency then you want events, if you're compute bound than you don't want that overhead.

EDIT: Instead of i7 just imagine any high end (high frequency and IPC) consumer chip