Honestly, ive ran all types of carbon. They work and there are benefits, but i dont run them now and my sps tank does just as fine. Growth is the same, colors are great.
As far as chemipure, the blue is great, but if you already run gfo, save the money and get the regular which will give you very similar results.
The best carbon hands down is Rox .08. Thing is you gotta be careful as a fresh batch will strip the tank fast of anything it can bind to.
I bought Seachem's Purfiltrum and regreted so much. It supposedly is much better than purigen, but ended up doing Ok at best.