Definitely a 10/10
One of the best selling for Pink Floyd, and there should be no surprise to that.
Because there is no other album quite like this... well, besides a few others by the same band themselves.
It's an entire life, trapped inside a album. It starts with a heartbeat, (literally,) and it ends with one. And in-between it talks about, depression, money and the bad things the love of it brings, brain damage, and death. It is a concept album, so it's definitely recommended to listen to each song side-by-side.
Guarantee you, mid way through listening, you'll find yourself staring off into space, thinking about life. Don't listen to it while you're working, you won't get anything done.
As for the age rating... I'd say, maybe a 10+
The first song on the album, 'Speak To Me' blurts out a sudden but almost inaudible f-bomb ("I've been mad for f*cking years",) and the song 'Money' also contains swearing, 'bulls**t.' ("Don't give me that do goody good bulls*hit.") And if you don't like the swearing, tough sh*t. It doesn't take away from the pure, unadulterated quality of the album.
It takes a smart one to fully understanding it's meaning, it's not just an album, as it is a story of life and it's hardships.
But, after all, i'd rank it below 'The Wall' (another album by Pink Floyd.) As the second best thing my ears have ever had the pleasure to listen to. I definitely recommend it. Now stop reading this little 13 year old bramble on about it, go listen to the album!