Big Petty fan here. My opinions:
Echo - single best Tom Petty album of all-time, bar none.
The Last DJ - solid album. Some great songs, some average songs. Still among his best. Last DJ, Money Becomes King, Joe, Have Love Will Travel, among the best of his/their career.
Highway Companion - another very solid album. Also probably among the best with songs like Square One, Saving Grace, Down South, and This Old Town.
Although I like most of their & his albums, I think all of the later ones are by far the best, starting with Mary Jane's Last Dance in '93. If you like the earlier stuff the most then you might not like the newer stuff, but if you're favorite is something like Full Moon Fever or Wildflowers, you should like them.