the highest tech would be the GHL Mitras then the radion pro. They are both high high dollar but the features are impressive.
The best bang for the buck IMO is the reefbreeders value and photon series. They have high PAR values and are customizable. The photon series have a bad butt touch pad and are programmable too.
I have a kessil a350w tuna blue and it's awsome but I just helped a neighbor install the RB photon 16 on his system and I was blown away at the power, color and controlability of the RB fixture. Not bad for a $315 dollar fixture!!!!!