Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Underrated

Everyone is quick to bash this album, even though it is perhaps their most progressive of all. Their sound had to change over their 11 year existence and it finally did on In Through the Out Door. Anyone who says the the synthesizers detract from the quality of the album is just being silly. If they kept with the same old style, which was not in any way getting old, they could not call themselves an actual BAND that makes actual MUSIC that actually has to CHANGE over time. They owed it to themselves, as well as the fans, to show everyone what they were made of and come out with something a bit different. In Through the Out Door is no better nor no worse than any of the other Zep masterpieces and anyone who thinks any different is really not a TRUE Zeppelin fan, but someone who is meerly finding small flaws in the greatest collaboration of talent ever put together. May Zep's music live on forever to show future generations what music should actually sound like.