Worth it if you own Rokits
If you have Rokit monitors like me (The 5) and want some headphones to complement and match the flat character of the Rokit, make informed mixing judgements while wearing headphones, then my advice is to buy the KRK 8400. My pair sounds almost exactly the monitors. A match as good as you could wish for in a headphone. So I can zero in with headphones with confidence and finish it off with monitors.
The KRK's have excellent clarity. It is a surgical cleanliness. My pair, is non-fatiguing out of the box. No harsh highs, no booming bass. The bass is on the lighter side, but it is there and keeping it light, where it doesn't bleed into the mids is one of the secrets to its clarity. Probably the most clear and flat headphones in the $150+ range. Don't get me wrong, it is still a balanced sound.
It is not perfect, bass is a tricky thing to evaluate in a bedroom studio, so you'll have to adjust for it, find ways (and equipment) to achieve proper levels. Keep that in mind. While mixing with the headphones, don't instinctively turn the bass up, it will be too much bass.