Wanting to switch to COB lighting

like the title says, I'm thinking of switching to COB lighting from traditional hps bulbs.

I need the lighting to match up with at least the 3 600w hps I currently have over a 4x8 area.

I am currently looking at two of the 600 Watt Citizen CLU048 4'x4'.
http://timbergrowlights.com/600-watt-citizen-clu048-4x4-framework/

Also maybe could do a build myself, I am pretty handy, I'm just getting lost with all the different components available.

Anyways, I would appreciate it if someone had a recommendation or if someone could point me in the right direction!

I'd go with:

1 http://timbergrowlights.com/600-watt-vero29-v7-4x4-framework/
and
1 http://timbergrowlights.com/400-watt-vero29-v7-square-framework/

You're currently outputting ~1250w of heat, after this upgrade it will be 515w of heat for the same number of photons; with added bonus of better PPFD averages. Heat in this context is anything but light.

If you DIY you can probably switch to the 50v or 70v Vero29 Gen 7 for greater efficiency and drive them a bit lower for the same price as the prebuilt. These timber fixtures are 48% efficient, the DIY route can be anywhere from 55-60% efficient for around the same price.