I’m a big fan of all the Halo amplifiers. Neutral, sometimes warmish. Never glaring or unmusical or weak. I traded mine in for ICEPower units, but not the bridged models. :) So it’s kind of funny these are the two options you are considering. Still, you can get those amplifier modules for cheap in a Ghent Audio case.
http://www.ghentaudio.com/amp/ga-s500p.htmlIf you are going that route, your total price may be better with a good preamp and outboard amps.
Still, I would say buy nothing you haven’t heard when it comes to a preamp and DAC. Each DAC chip has it's own quirks that must be addressed properly by the designers. There's good ESS and bad ESS. The total package sound matters.
BTW, you’ll never use the 450 watts. The only way I would think that was a plus is if the 1 watt distortion and noise figures were better, and they rarely are. You may want to look at the smaller amplifiers at Ghent, they’ll be much more cost effective.
Best,
Erik