I'm glad someone brought up Van Halen.
This is seriously a scenario in which we're comparing two entirely different bands, even though there was only one personnel change.
I became a huge Van Halen fan in the early 80s. Loved ALL of the DLR-era albums.
When Sammy Hagar joined the band, I refused to listen to 5150. Of course, I really couldn't avoid it altogether with the heavy radio play. But I dismissed it as pop crap.
I finally caved and listened to the album. And I instantly fell in love with it. 5150, OU812 and F.U.C.K., were all fantastic albums. After that ... junk, IMO. I won't even acknowledge the Gary Cherone album.
The DLR albums and the Hagar albums are nothing alike. It's seriously like two different bands/two different genres. And two awesome bands. I seriously can't even say which era I like more. Love 'em both.