For me, the biggest difference is that we never actually meet Mr. New Vegas (and yes, I know why)
In FO3, you meet 3 Dog. And it's not just "maybe" you meet him, he's part of the main quest line. You also get some side quests from him, you help extend out his broadcast range, and you can go visit him if you want.
So IMO, even if the actual music was 100% identical, I would prefer the FO3 radio because I relate better to the voice in between the songs. That's the glue that holds it all together. When I listen to the radio in the ruins of DC, I know that the reason it's broadcasting there is because of me.
Tangible effects + relatable characters = better radio. Simple. Oh, and the guitar song gets on my nerves a bit, too