I think it's just a different mastering. It's not about frequency and bit-depth itself, but about marketing policy of some labels which issue in high-res recordings with different mastering. For example ZZ top complete studio box-set has no reverberation as in first press CD of the same albums. Also Metallica post 1991 Hi-res albums are slightly better than the same original CDs. The same is for a couple of Motorhead albums. In all that cases it's just mastering, as a proof I can assert that the sound/mastering result does not depend on frequency, as I listen to all the mentioned above as FLACs on my PC and as lossy (AAC) on my smartphone.
So look for mastering, but not exclusively for hi-res.
P. S. If the Hi-res version doesn't have better mastering (and of course worse one) you can use it to prevent resampling on the target device though