Fortunately, or unfortunately "the best" in DIY is pretty subjective.
Second LED's themselves are continuing to develop and expand..
Price changes, heat tolerances, CRI, eficiencies are all in flux..
so the best thing is for one to start w/ lists of needs/wants
do you want control? how much?
do you want a warm or cool look to the tank?
do you want high par low par?
how much does one want to spend?
where are you placing it? Hanging? hood?
size of tank, depth of tank, high or med or low light
complex build or simple..
almost all those are independent of the diode brand though some do have an impact.
CREE, Bridgelux,Luxeon, Luminous Devices, "epistar" or cheap eek bay "eggs" all work, all have been used..
CREE is fairly a winner w/ efficiency but generally low on CRI.
I personally, if building a "simple" fixture would choose mostly Luxeon's.
The actual needs here don't really lead to a 'pick the best" diodes really..
no CREES but lots of colors and lots of power....