Mix intensity with alternating cheer or gloom, and you can sum up Flyleaf. It's worth a listen on imeem.com, at least.

The music alternates from cheerful to gloomy, as I said before. (You'll notice, I am sure, that I wind up writing like this a lot) It's got catchy tunes and nice guitar (I'm no expert, it could be another instrument) and I find the singer's voice wonderful, and the lyrics are often cheerful, if you listen right.

I give it a 4/5, like everything else, and I'll be listening to it for a while.

P.S.: Yes, I know what "memento mori" means. If you don't, Wikipedia will oblige.