I loved his first album, which I bought as a British import upon it’s initial release. I then liked his second, but didn’t really care for The Attractions. Steve’s piano playing is far too busy for my taste (too many single notes and "tinkling", not enough chords), and the drummer is typically British---not a "pocket" player, instead playing "on top" of the music. The third album I could never get into, and Costello’s ever-increasing vibrato was starting to annoy me. That vibrato is now, imo, completely over-the-top, way overused and excessive.
He then starting doing "theme" albums---a Country music one, a Soul music one, both of which revealed him to be a sincere fan of the music, but a not-particularly distinguished purveyor of it. He's no George Jones or Hank Williams, nor Sam Cooke or Otis Redding. I pretty much lost all interest in him after that. Yup, he’s a talented guy, but the only album of his I kept when weeding out my music collection recently was the King Of America album, his least "British" sounding---no surprise there!
I had a good friend (R.I.P.) who was an excellent songwriter, and a big fan of Brian Wilson and Bob Dylan. I played him the first album, and he didn’t get it. I moved to L.A. in ’79, not seeing him again until the mid-2000’s. By that time, Costello had become his favorite contemporary Pop writer, and he actually said to me "Who needs Brian and Bob when you have Costello?". Then I played him Bob’s Love And Theft album, and he got the answer---HE did!