The article is over a year old. Moore's Law should be taken into account here.
OP is going to need focused optics and a well driven set of LED's. Mosty ready-made systems aren't going to cut it and en masse would cost too much to be effective in comparison to a MH setup, however if he can make his own LED system, it should far surpass MH in all fields including startup and running costs.
There's a multi-part series on YT regarding making an LED system from scratch. I believe it's from an author called "Ricket's Reef." It's a very simplistic/broken down way of how to purchase and wire LED's.
