XM 10ks are about the best bulb for growth sans the Iwaskis but are too yellow for me.
The Hamilton 14k and the Reeflux 14ks look nice but have less PAR than the XM 20ks
The Reeflux 10's look white but have caused more actinic color change to my acros that the 14ks ever did and the growth is better.
, pick a bulb that has the color you like. Running suppliment lighting will allow you to fine tune it a bit.
I run 3 250's, 2 54w T5's and 2 55w PCs over my 180. I know a guy that is running 3 150's and likes it. It is all personal preference. I have 3 clams and a lot of SPS
so I think the 250s are for me. I could not imagine running more lights than I do but I know some that do that too.