Beyond looking at the magnum and seeing some decent grow journals I can't offer much first hand experience. I didn't buy the magnum because the cost per watt was way high compared to the PG.
If you check back through this journal you'll see I've grown with lamps containing bridgelux, epistar, orsam, and cree diodes. Crees are number one for a reason. The output on some cree high output 3w diodes, used in the PGs, will leave others in the dust.
The lumigrows are also hyper expensive for what you get in terms of actual output. Also a marketing rep from monster gardens (people who sell lumigrow) decided to use this journal to spam people about how great their lights are. For that reason alone I will never buy one.