The non-compact is definitely enough...it's 28" wide and provides great coverage and deep penetration. Brs did a nice review of it. Provides a good compromise of shimmer and lack of harsh shadows without disco effect, which I hate. I found the single lens lights like the Kessils (and I suppose the redsea) overly shimmery, but that's just my taste. I actually didn't like the XR15 gen4's disco effect, but with the diffuser it was great.
I love the ability to get deep violets on the Radions and the Orpheks, and wasn't too fond of the windex look of the Kessils (and looking at the reviews the Redsea).
I find the Orphek is quieter than the Radion Gen 4, and it sounds like the Gen 5's are no quieter.
What really sold mo on the Orphek over the Radion (that I had before) was that I HATE the glare of the light when you're looking at the tank, and the Radion's are very glarey. The Orphek's lenses don't allow much light at all outside the tank. I wasn't fond of the thick exposed plexiglass at the bottom that kind of glowed, so I put some black tape around it and it looks like it was meant to be there.
All just personal preferences....been through a lot of different lights and ended up with this one and I really like it.