These tracks were recorded in the last eighteen months of Elvis' life, and everybody has a different opinion about them. I suspect that the real reason some people dislike them is their obvious country orientation.
There are plenty of country songs here, including If you love me let me know (Olivia Newton-John), He'll have to go (Jim Reeves), She thinks I still care (George Jones), Blue eyes crying in the rain (which Elvis probably covered after hearing Willie Nelson's cover of Roy Acuff's song) and Bitter they are harder they fall (Larry Gatlin). For the heart later became a country number one for the Judds, under the title Had a dream.
Unchained melody, which opens this set, has become a pop classic everywhere, but nowhere more than in Britain, where it hits the upper reaches of the charts every few years. It has been number one for three (maybe four) different artists at different times, making it (arguably) the most popular song in British chart history. Elvis' live version is not the best version of this song, but it's reasonable.
Other pop classics covered here include Pledging my love (Johnny Ace), Hurt (Timi Yuro, later a country number one for Juice Newton), The last farewell (Roger Whittaker), I'll never fall in love again (Tom Jones), Solitaire (written by Neil Sedaka, but the Carpenters and Andy Williams each had hits with it).
The old Irish folk song Danny Boy also gets a nice workout. The big hits, Moody blue and Way down, were successful on both the pop and country charts.
So, this may not be the best of Elvis, but it's a great album for country music fans to have. If you don't like country music, there are plenty of other albums by Elvis that will suit you better.