I know some pirates have lived with the NAD M51, so I'm curious if the Gungnir Multibit is a worthwhile upgrade. I've downscaled from a Ragnarok driving the HD650/HD800 to just a Valhalla 2 and the HD650. Really enjoying this modest rig, particularly with Amperex Bugle Boys rolled in the V2. I suspect the V2 may just be resolving enough to present the difference between the M51 and Gungnir Multibit. I am also quite content with the M51. I don't find myself wanting for more in terms of SQ, and I certainly appreciate the features (great preamp, volume control with remote, and hdmi input/pass-through) that are still absent from newer dacs. The accolades thrown towards Schiit's R2R implementations have me itching to hear what the fuss is about though. Can't justify the Yggdrasil for now, and I suspect the Bifrost Multibit would merely be a side-grade, so the Gungnir Multibit looks the logical option. Anyone care to wax lyrical on the difference between the M51 and Gungnir Multibit?