IMO people are PAR crazy these days. Granted mine is SE on an e-ballast, but it's plenty bright and the color is oh-so-cool.

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Meaning what? When people say it's plenty bright I never know what to think. Do you think we give to much PAR or it's not important or what? I haven't really seen people decreasing PAR significantly causing good growth rates. I mean I want it to look good also but not at the sacrifice of growth! That's what they make actinics for!"]
Meaning that the highest possible par number is not necessarily the best thing for your tank. Sanjay rated the 250W CV Reeflux 10K SE on an IC e-ballast (closest to my ARO) in the high 80s. Can I get a higher PAR from a different bulb? Definitely. Do I really need it? In my opinion, no. I've seen the XM 10Ks and they're OK. Bright, yes, pretty, not really. Ushio 10Ks - bright as hell, ugly as hell. With the Reeflux I feel I've struck the right balance of color and growth.
My tank isn't especially deep (12" right now, the next one will be 17") so I don't need to blast every possible spot. Even with my measly 80something PAR (PPFD, whatever

) I think I may have a little too much light.
My other consideration (and this is a personal one) involves electricity consumption. Maybe I'm splitting hairs, but I'm happy that I can get the color and the growth out of one bulb and don't need to (needlessly?) burn VHO tubes (which are pretty inefficient) or T5s (more efficient but still a lot of W) to get color correction. As a conservationist and sustainability buff, it makes me all warm and fuzzy inside to use just what I need and no more.
But that's a personal choice. Some day down the road, we'll all be MUCH more energy concious. Hell, there may be a point where we have to shed ourselves of luxuries (like reef aquariums) just to survive, but that's a discussion for another thread.