Its more challenging than your average shooter, even on easy, if you play it that way. As a stealth game, I find it to be phenomenal.
I mean you can die from a good distance (say 15 or so feet) from a shotgun in a couple hits, so cover is essential. Honestly it's easier to win shootouts on gears of war hardcore without using cover than in DXHR easy.
But the setting, music, and story are all top-notch, and the difficulty curve can be easily overcome. On my second playthrough I had 12 grand sitting around and 6 praxis kits I didnt even have to use before the first boss.
People will claim it railroads you into stealth for more experience but unless you are a god at takedowns or patient you will miss a good portion of loot, so just play it how you will, I know from experience that both approaches are great.
So yeah, get it. It's the only game this year besides dark souls and skyrim that I have bought on release and kept. Every other game I was satisfied with a rental.