Buckster....not nearly a scientific review, but I own an Elite SC 27 (predecessor to the SC 37), an SC 05 before that, and have demo'd the Anthem (MX 700) in a showroom. The obvious difference is ARC in the Anthem. The SC has a more muscle (ICE AMPS), though. I'll say up front, I love the SC series from Pioneer Elite. They're smooth sounding, and powerful. They're built like tanks, too. They're easy to set up, and to use.
Understand, different room (but same speakers) will yield different results. ARC does some nice things. So does Pioneer's MCACC. Do I prefer one over the other? I can't make that claim unless I had them both in an A/B comparison in my system.
As far as the Denon is concernced...like Pioneer, they've been in the AVR business a long time and make good gear. The 4XXX series hovers at the top of their lineup....as does the SC series in Pioneer's Elite lineup. Both are good to great AVRs.
I'm not a fan of Onkyo/Integra. I test drove, in my system, both an 805/875. Way, way too many issues with both. Maybe they've fixed those issues in subsequent releases. Twice was all I needed to steer me away from them, though.
Anthem? Personally, I'd wait a bit until their 2nd or 3rd gen of AVRs. While they make great pre-pros and amps. AVRs are a different animal and difficult to do well. Ask Emotiva or Sherwood Newcastle.
Music so high you can't get over it....music so low you can't get under it!