I just setup my V4 today......so to say they are better than my T5s they replaced is a bit early. That noted, I'm quite impressed with the Orphek v4. I am in fact ordering two more to replace the lighting in my other LED based system.......
Really meets or exceeds expectations.
If you used 3 panels over 4.5 ft perpendicular to the tank it means the lights are sufficient to light 1.5ft of tank length mounted back to front. Doesn't that mean 4 panels will be sufficient for 6ft of tank length? You mentioned this was "good" coverage and not just "sufficient"
I have a vested interest in the answer too... I'm seriously tempted by them Orpheks myself!
I haven't been able to bite the bullet yet considering that I'm running very new Radion g4 pros. My lfs uses them on his show tank and he likes them alot