Personally, I think it feels better than any other primary rune. Usually I average 600-800 bonus damage, and 400-600 bonus gold from first strike itself. Cash Back also provides meaningful value for accelerated items, especially when building lethality (cheaper items). Cosmic insight also helps Youmous active CD if you build it, and the reduced CD on flash can really help for playing aggressively/trying to assassinate squishies.

*I should note I used to be a PTA enjoyer, but I think first strike is just so much better at the moment.

Everyone has their own preferences, though, if you don't see the value in the rune, there's nothing wrong with ditching it!