I've never been that keen on the Necron Destroyer models, but rule-wise I think the Destroyer Lord works well in allied detachment with some Wraiths. I will write a post on magnetising Wraiths for practical storage and transport.
I don't think the warscythe looks very graceful or aerodynamic. I imagine the Necrons to be very effortless in their movement. However, preferred enemy is too good to turn down so I can live with an awkward scythe.
An easy conversion overall - a standard Necron Tomblade with the Overlord's head & scythe from the Annihilation barge.