I'll be the dissenting voice here, I love the heart system and find the 5-star overly cumbersome.
My problems with the 5-star ratings are:
- Ambiguous Meaning. What does 1 star mean? Some people's scale goes "1-Hate, 2-Dislike, 3-Whatever, 4-Like, 5-Love", while others use "1-Meh, 2-Interesting, 3-Like A Lot, 4-Love It, 5-OMG Best Song Ever". Those are just the two most popular, I've seen even weirder systems. This is fine for a soloist but when sharing music with my wife or letting friends browse my lists I was always having to explain what 1 star meant vs. 5 or my wife would rate a song with 1 star and I'd ask her why she hated it but she had meant "I like it a bit". Heart vs. Broken Heart is pretty obvious to everyone what is meant.a
- Preferences Change. When I first buy an album I often really love a certain track, giving it 5 stars yet after a few listenings it becomes a 4 or 3 star. Same issue the other way, the last Red Hot Chili Pepper's album I picked up didn't grab me at first so most things were 3 stars but after a few more listenings a lot of songs went 4 or 5. With a heart/broken-heart songs rarely jump from one state to another and I do less "rating maintenance".
- No Return On Investment. I had thousands of songs all rated from 1 to 5, but I did nothing with the information. At the most I would create an auto-playlist with all 5-star tracks yet after a week of listening I grew sick of some tracks and wanted some 4 star as well then turned into wanting everything 3+, which is exactly what a heart is, something that stands out from the rest.
- Cluttered. Put a list of a 100 tracks rated 1 thru 5 next to the same list rated heart/broken heart you'll be able to pick out the stand-out tracks much quicker in the heart list.
So while my inner nerd loves having 5 stars to microrate things the information wasn't useful. When I did use it it was in such a vague way, like a playlist with all 3+ stars, than I may as well have only had a single rating, thumbs up.
It's very similar to how I use movie reviews, it's not like I only see 4+ star movies. I just want to know if it sucked (broken heart),was OK, (no rating) or was good enough to see (heart). This is also very similar to when you read album reviews. I have rarely read an album review where they said, "Well, the first and last track was 5 stars but the middle ones were more like 3 star tracks." Usually a review is more like, "Well, the first and last tracks are really good but the middle three were blase".
I'm sure there is a small subset of people that really do use all 5 of those stars in a daily and useful way but the heart/broken-heart method has actually made rating much easier and more useful. For the average consumer things are usually rated thumbs up/down, it sucked it/it rocked, buy/don't buy, or heart/broken-heart.