This guy is pretty high on the TMC GrowBeam lights for planted tanks:
His article shows a 12 watt TMC GrowBeam beating a 175 watt metal halide:
I'm not sure about the conditions of that test and he claims that TMC has exclusive rights to a particular high-PAR LED from Cree, which I have not confirmed.
However, it does look like an interesting option.
[EDIT: After reading the article again, I'm not sure if that test uses the TMC LED]