I'm using the PowerSun 100W for my Basking spot and UVB/Visual Light and I'm also using a 24 Inch ReptiSun 10.0 UVB Tube for more UVB and Light and a Normal Clear House Hold Bulb "60W" as I have a Big Enclosure and need more light.
The MegaRay has been tested on the Wave Length of UVB it put's out and how many month's it last and how consistent it is. And test's shown it be the Best of the MVB bulb's.
The PowerSun has also been tested the same way, and it came in a Close 2nd Place, but many people on here use PowerSun's. I actually only know of 2 people on here that I have seen use MegRay.
And even tho MVB Bulb's produce Heat/Light/UVB which is everything your Beardie Need's from a light source, it is still very good to use a Normal House Hold Bulb that is Clear, or just a Normal Florescent Tube & Fixture from Walmart on the cool end of the Tank or Middle of the Tank to add some extra light.
Ohh ummmm, Well I know zoomed also sell's "NaturalSun's" or something like that name, and it's just Visual Light/UVA you could to brighten up the Enclosure. If that's what you're wanting to do xD Pretty sure the cost a lot less too.
For background light opinions differ, but 5000 to 6000 Kelvin is good ( I use a 6500 myself). As for CRI get the highest rating you can, I think 85 and up would be considered acceptable.
Fwiw I just got my first megaray a couple weeks ago, the beardie seems to like it just fine.
For the record, you don't need background UV - let your animal decide when they need it. Just keep your temps right so it can comfortably photo/thermometer regulate.