Denon as transport - a month on. DAC dominates?

So I've enjoyed having my Denon UD player for a month now (and have sold my long serving Arcam 92 CDP, so no going back!!) and a few thoughts have taken up residence. Can anyone offer opinions, profound insights or simple blind prejudice to my questions?

Does my NAD DAC minimise the differences between say higher resolution discs (DVD-A and SACD, for example) and standard CD? I have a small collection of the former and they sound good. Really good. Yet when I played them alongside the CD or Lossless version of the same track I noticed few major differences. DVD-A, perhaps, sneaked it, but the Lossless rip from the CD of the same material sounded virtually the same/as good on most occasions. 

Blu-ray audio sounds great too, in the right hands, but even then the CD or Lossless versions weren't too far behind. Some sounded very similar to me. 

The biggest differences, so far, in so called hi-rez versus standard has been when I've tried a few 24bit LPs through the USB port. 

So should I be pleased that my system (see below) makes most music sound good, regardless of bit & sampling rates or should I be disappointed that there isn't more daylight between the formats?

For reference most of my digital listening during the last month has been with the following:

DVD-A : Talking Heads' Speaking In Tongues, Remain In Light, Little Creatures; various Neil Young LPs

SACD: Tommy - The Who, various orchestral pieces, (Bartok, Nancorrow, Carter, Varese), Dylan. 

Blu-ray: Neil Young's Archives Vol.1, Zep's Celebration Day, Lou Reed's Berlin, Radiohead's From The Basement

24 bit files: George Harrison Early Takes, Steely Dan's Gaucho, Rush's Moving Pictures, Peter Gabriel's So & Scratch My Back, various MMJ live shows, Paul's Boutique by The Beastie Boys and King Of Limbs by Radiohead.